• Bulletin of the Korean Chemical Society
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• 제23권3호
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• pp.469-476
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• 2002

Photocrosslinkable soluble polyimide and polymethacrylate compound were synthesized for studying the optically induced anisotropy of the thin films. Chalcone group was introduced into the side chain unit of two polymers. We observed a photodimerization behavior between the double bonds in the chalcone group and an optical anisotropy of these materials by irradiation of a linearly polarized UV light (LPL). Optical anisotropy of the thin film was also investigated by using polarized UV absorption spectroscopy. The dynamic property of optical anisotropy in photoreactive polyimide was compared to that in polymethacrylate containing chalcone group in the side chain.

• 한국광학회지
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• 제20권5호
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• pp.281-287
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• 2009

편광법을 사용하여 패턴이 있는 LCD 유리기층위에 놓여 있는 러빙된 PI(polyimide)의 광학이방성을 분석하였다. 투과형 편광계를 사용하여 0.4 nm 이하의 극히 작은 위상지연의 크기와 광축의 방향을 정밀하게 측정하였다. 온도에 따르는 광학이방성의 미세변화를 위상지연의 크기 및 광축 방향의 변화곡선으로 나타내고 간단한 광학모델을 사용하여 설명하였다.

• Journal of the Optical Society of Korea
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• 제18권2호
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• pp.156-161
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• 2014

Anisotropy profile of a rubbed polyimide film is investigated using both a modified ultra high precision transmission ellipsometer and the analysis software previously developed to determine the optic axis distribution of discotic liquid crystals in the wide view film. The distorted sinusoidal variation of the ellipsometric constants obtained at an oblique angle of incidence indicates that the optic axis varies from $14.7^{\circ}$ to $40.6^{\circ}$ from the sample plane. The magnitude and distribution of anisotropy is expressed in terms of no, ne, and the cosine-shaped tilt angle distribution of the optic axis in a rubbed polyimide film.

• Journal of Magnetics
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• 제20권1호
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• pp.8-10
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• 2015

The magnetic anisotropy field plays an important role in spin-orbit-torque-induced magnetization dynamics with electric current injection. Here, we propose a magnetometric technique to measure the magnetic anisotropy field in nanostructured ferromagnetic thin films. This technique utilizes a magneto-optical Kerr effect microscope equipped with two-axis electromagnets. By measuring the out-of-plane hysteresis loops and then analyzing their saturated magnetization with respect to the in-plane magnetic field, the magnetic anisotropy field is uniquely quantified within the context of the Stoner-Wohlfarth theory. The present technique can be applied to small nanostructures, enabling in-situ determination of the magnetic anisotropy field of nanodevices.

• 한국광학회지
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• 제23권6호
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• pp.274-280
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• 2012

기존의 반사형 타원계에 광분할기와 프리즘 등의 광학소자를 추가하여 $8.0{\mu}m$ 보다 작은 면적에서 시료의 광학이방성을 측정할 수 있는 수직반사형 타원계를 제작하였다. 수직반사 구조를 구현하기 위해 사용된 광학소자들의 편광작용을 보정하여 광학이방성 측정의 정확도를 향상시켰다. 비편광 광분할기를 사용하고 사분파장 위상지연자를 장착하며 광섬유를 제거하고 파장영역을 최적화하여 광학이방성인자 측정값의 표준편차를 0.00083 으로 줄이고 방위각 변화에 따른 rutile 시료의 광학이방성인자의 변동폭을 0.015 이하로 줄일 수 있었다.

• 한국광학회지
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• 제26권4호
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• pp.195-202
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• 2015

기층의 잔류 이방성에 영향을 받지 않고 러빙된 폴리이미드 배향막의 초미세 광학 이방성을 정밀하게 측정할 수 있는 반사형 타원계를 개발하고 러빙의 세기를 달리하여 제작한 배향막의 광학이방성을 이 반사형 타원계를 사용하여 측정, 분석하였다. 투과형 타원계를 사용하여 측정한 리타데이션과 비교하여 개발된 반사형 타원계의 신뢰도 및 광학 이방성의 측정 재현성을 확인하고 배향막의 형성 여부와 배향막의 형성정도를 정량적으로 평가하였다

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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• pp.399-400
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• 2008

The light efficiency of fringe-field switching (FFS) mode when using a liquid crystal (LC) with positive dielectric anisotropy was found to be dependent on the magnitude of dielectric anisotropy, such that the lower dielectric anisotropy, the higher. We studied out not only light efficiency but also response time according to dependence on the magnitude of dielectric anisotropy. Rising and decay time became fast and slow respectively according to decreasing the magnitude of dielectric anisotropy. This paper investigates electro-optical characteristic of FFS mode using LC with a positive dielectric anisotropy dependent on the magnitude of dielectric anisotropy of the LC.

• 한국광학회:학술대회논문집
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• 한국광학회 1988년도 광학 및 양자전자학 워크샵
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• pp.127-131
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• 1988

In order to clarify the origin of perpendicular anisotropy in thermally evaporated TbFeCo amorphous thin films, we have investigated the effects of deposition angle on magnetic Kerr hysteresis loop, perpendicular magnetic anisotropy and internal stress depend strongly on the deposition angle and above a threshold value(30$^{\circ}$), the perpendicular anisotropy disapperars and the in-plane anisotropy appears. The measurement of internal stress is the major contribution to the perpendicular anisotropy. The measurements of Kerr hysteresis loops in the polar and the longitudinal directions show that as the deposition angle increases the polar kerr hystresis loop deteriorates while the longitudinal Kerr hystersis loop becomes prominent.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1351-1354
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• 2005

We report on the photoalignment process of pentacene thin film with optical anisotropy on treated buffer layers. The photopolymer, showing an anchoring transition, was used as a buffer layer to control the structural order of the pentacene molecules. Using the photoelastic modulator, it was found that the grain size and the optical anisotropy of the pentacene thin film were strongly correlated with each other.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.288-288
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• 2009

We have studied polarity effects of dielectric anisotropy effects on electro-optical characteristics of a twisted nematic mode driven by fringe electric field, which has wide viewing angle characteristics. Our device is designed as normally black mode between parallel polarizers. The perfect polarization conversion of incident light, which passes through a polarizer, is achieved, when it passes through the twisted liquid crystal (LC) layer. If an electric field is applied, the LC molecules with a positive (or negative) dielectric anisotropy rotate parallel (or perpendicular) to the horizontal component of a fringe electric field as increasing transmittance. From the calculated results, enhanced transmittance of the fringe field-twisted nematic (FF-TN) mode with positive dielectric anisotropy of + 8.2 can be obtained.