• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1933-1935
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• 2002

In this paper, we present a study of the structure and electro-optic behavior of hybrid liquid-crystal-silica sphere composite photonic crystals, formed by filling the (26% by volume) void space of fee (face centered cubic) silica opals infiltrated with a nematic liquid crystal. Three dimensional photonic crystals of visible range were fabricated via a self assembly method of silica spheres of submicron diameter. The expected fee structure was confirmed by scanning electron microscopy (SEM) of the dehydrated crystal with glass removed. The photonic crystal exhibited significant electric-field-induced shift of the optical Bragg reflection peak when the liquid crystal has the long molecular axis oriented parallel to the sphere surfaces.

• 한국전기전자재료학회논문지
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• 제16권10호
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• pp.908-913
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• 2003

We have performed computer simulation to obtain electro-optic characteristics of reflective hybrid aligned nematic liquid crystal displays (LCDs) driven by fringe field. The results show that the optimal retardation value (dΔn) of the cell is 0.289 ${\mu}$m, which allows for the cell to have a practical cell gap of larger than 3 ${\mu}$m when manufacturing. A reflectance of the dark state is only 0.114 % for an incident light 550 nm. At this condition, the light efficiency of white state reaches 92.7 %. The display with optimized cell parameters shows that the contrast ratio greater than 5 exists over 600 of polar angle in all directions and lower driving voltage than that of fringe-field driven homogeneously aligned reflective LCD.

• 한국전기전자재료학회논문지
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• 제17권5호
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• pp.530-535
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• 2004

We have studied 90$^{\circ}$ twisted nematic mode switching by fringe electric field(F-TN mode) using a liquid crystal (LC) with negative dielectric anisotropy. In the device, two polarizers are parallel each other, electrodes exist only on bottom substrate, and one of rubbing direction is coincident with polarizer axis. Therefore, the cell shows a black state before a voltage is applied. With a bias voltage generating fringe-electric field, the LC twists perpendicular to fringe electric field such that the LCs are almost homogeneously aligned except near the bottom surface since the negative type of the LC is used. Consequently, the new device exhibits much wider viewing angle than that of the conventional TN mode due to in-plane switching and relatively high transmittance since the LC director above whole electrode area aligns parallel to the polarizer axis.

• 한국통신학회논문지
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• 제25권1B호
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• pp.42-47
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• 2000

버스트 모드 패킷 트래픽 조건에서 스위칭 소광비를 최대화하는 전기 광학 광변조기의 바이어스 안정화를 위한 새로운 방법을 입증하였다. 광변조기의 오프 레벨 출력 전력을 샘플링하고 최소화함으로써 패킷 트래픽 밀도의 변화에 무관하게 높은 소광비를 갖는 광 게이트로서 동작한다

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2000년도 제1회 학술대회 논문집
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• pp.43-44
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• 2000

The fringe-field switching (FFS) display is known to exhibit wide-viewing-angle and high transmittance. We have simulated pretilt effects on electro-optic characteristic of the device when a liquid crystal with positive and negative dielectric anisotropy is used. The results show that asymmetry in contour of luminance and light leakage in the dark state are increased but voltage-dependent transmittance curves remain about the same, as the pretilt angle increases to $10^{\circ}$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1987년도 정기총회 및 창립40주년기념 학술대회 학회본부
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• pp.220-223
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• 1987

In this paper, electro-optic characteristics of PLZT 7.6/70/30 composition in MPB regions, which antiferroelectric and ferroelectric phases coexist together, were studied. As sintering times are increased, Curie temperatures ore linearly decreased. And the antiferroelectric phase becomes more stronger when Curie temperatures are decreased. The crystal structure investigated by lie of X-ray analysis is proved to cubic in the thermally depoled specimen and rhombohedral in the poled specimen. Accordingly, the applicability of 7.6/70/30 specimen as image storage and display device is expected by the method for applying field induced reversible transitions between antiferroelectric(AFE) and ferroelectric(FE) phase.

• 한국광학회:학술대회논문집
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• 한국광학회 2003년도 제14회 정기총회 및 03년 동계학술발표회
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• pp.154-155
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• 2003

반도체 소자에 있어서 굴절율의 변화는 중요한 역할을 한다. 굴절율을 변화시키는 다양한 요소들은, 전계에 의한 1차 전기광학(linear electro-optic： LEO) 효과와 2차 전기광학 (quadratic electro-optic： QEO) 효과, 자유 운반자에 의한 밴드천이(band-gap shift： BS) 효과와 플라즈마(plasma： PL) 효과 등으로 잘 알려져 있다. 본 논문에서는, 오로지 TE 모드에 대해서만 선택적으로 위상 변화를 주는 P-I-i-I-N GaAs／Al／sub0.35／Ga／sub 0.65／As 도파로 위상변조기를 보고한다. (중략)

• Bulletin of the Korean Chemical Society
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• 제23권7호
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• pp.964-970
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• 2002

We synthesized three kinds of chromophores incorporating aromatic quinoline unit as a $\pi-conjugated$ bridge in order to prepare more thermally stable nonlinear optical (NLO) chromophores than general stilbene unit. The NLO poly(methylmethacrylate) copolymer, polyimides, and polyester were successfully synthesized by these corresponding quinoline-based monomers. Their physical and optical properties were investigated by thermogravimetry, gel permeation chromatography, ultraviolet-visible spectroscopy, second harmonic generation (SHG) and electro-optic (EO) measurement. All the polymers exhibited better thermal stability,however their NLO activity was a little lower than that of general stilbene-based NLO polymers. Among three kinds of polymers, the PMMA copolymer with quinoline chromophores had the largest SHG coefficient d33 value of 27 pm/V (at 1.064 $\mu\textrm{m})$ and EO coefficient r33 value of 6.8 pm/V (at 1.3 $\mu\textrm{m}$).

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.902-903
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• 2009

Polymer Dispersed Liquid Crystal (PDLC) films were prepared using the phase separation method with liquid crystal and a newly developed prepolymer. This study investigated the electro-optic characteristics of the PDLC film at various temperatures. It was found that as temperatures increased, the voltage varied, and that the ordinary refractive index of the liquid crystal and the polymer refractive index in the composite had similar dependence at various temperatures.

• 대한전자공학회논문지
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• 제7권2호
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• pp.1-12
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• 1970

본 논문에서는 선형전기광효과(Pockel 효과)를 이용하여 X대역 마이크로파(9375 MHz)를 광변조하는데 관하여 이론적인 해석과 실험적인 연구를 했다. 전기광 결정체 KDP를 공진형 변조기로 설계하여 z축으로 광선과 평행하게 마이크로파 전계를 인가하여 변조했다. 변조파 출력을 가변단락판의 위치변화에 따라 관찰했으며 /2에서 변조가 잘 개폐되는 것을 알았다. 또한 출력변조의 세기를 인가 전계의 세기를 변화시켜 측정하여 이론곡선과 비교해서 약 5%의 오차를 얻었다. 결과적으로 아직 해결되어야 할 문제는 많이 있지만 비교적 만족스러운 광변조기를 얻었다.