• 전자공학회논문지A
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• 제33A권5호
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• pp.125-131
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• 1996

In this paper, we introduced the BQBPH method for making the grating of high efficiency which was improtant in implementing optical PS. The pattern of graing was obtianed by computer simulations using iterative method, and the diffraction efficeincy of designed grating was about 67% through BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency BPM simulation. The grating was fabricated by laser beam writer, and the diffraction efficiency was 47%. We implemented the optical PS with the grating and showed that optical experimental output patterns were good agreement with PS output patterns and first order was main diffraction order.

• Journal of the Optical Society of Korea
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• 제18권5호
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• pp.485-494
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• 2014

A novel antenna with ellipsoid-paraboloid surfaces configuration is designed for matching the incident radial radiation fiber laser distribution for maximum transmission efficiency. The on-axial and off-axial defocus effects on the optical antenna system, resulting in energy loss, are analyzed in detail. Knowledge of the effects of those defocuses on beam divergence, aberration and antenna transmission efficiency is of great importance to the long range communication systems.

• 한국광학회지
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• 제21권1호
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• pp.26-32
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• 2010

플라스틱 광섬유의 주기적인 bending을 이용한 누설광섬유에 기반을 둔 라인램프를 제안하고, 그 핵심요소로서 높은 광결합효율을 갖는 LED-광섬유 결합기를 설계 및 해석하였다. Monte Carlo photon simulation 기법을 이용하여 해석한 결과, 결합기의 광결합효율은 반사컵 옆면의 기울기각 $\theta_w$와 반사컵의 반사도 $\rho_{ref}$에 대해 상대적으로 민감하게 영향을 받는 사실을 확인할 수 있었다. 광결합효율은 $\theta_w=60^{\circ}C$ 근처에서 최대가 되었는데, 이 값은 일반적인 LED 램프에서 흔히 사용하는 반사컵 옆면의 기울기각 $\theta_w=45^{\circ}$보다 상당히 큰 값이다. 그리고 반사컵의 반사도 $\rho_{ref}$가 0.8정도 이상이 되면, 광결합효율은 보통의 LD-광섬유 결합기에서 얻을 수 있는 광결합효율인 80% 정도를 뛰어 넘었다.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.745-751
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• 2016

A detection algorithm, based on the combined local-global (CLG) optical-flow model and Gaussian pyramid for a moving target appearing against a dynamic background, can compensate for the inadaptability of the classic Horn-Schunck algorithm to illumination changes and reduce the number of needed calculations. Incorporating the hypothesis of gradient conservation into the traditional CLG optical-flow model and combining structure and texture decomposition enable this algorithm to minimize the impact of illumination changes on optical-flow estimates. Further, calculating optical-flow with the Gaussian pyramid by layers and computing optical-flow at other points using an optical-flow iterative with higher gray-level points together reduce the number of calculations required to improve detection efficiency. Finally, this proposed method achieves the detection of a moving target against a dynamic background, according to the background motion vector determined by the displacement and magnitude of the optical-flow. Simulation results indicate that this algorithm, in comparison to the traditional Horn-Schunck optical-flow algorithm, accurately detects a moving target undergoing illumination changes against a dynamic background and simultaneously demonstrates a significant reduction in the number of computations needed to improve detection efficiency.

• 반도체디스플레이기술학회지
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• 제10권1호
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• pp.91-94
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• 2011

This paper presents light transmission efficiency by optical adhesive thickness between MLA and aperture layer and by aperture hole size. The gap between MLA and Aperture layer is adjusted by the shim. The more optical adhesive thickness increases, the better light transmission efficiency increases up to a point. After that, the light transmission efficiency decreases because stray lights cannot transmit through the aperture layer owing to cut-off by aperture layer. And as a result of light transmission efficiency with changing aperture hole size, the light transmission efficiency is proportional to area of aperture hole. The more specified process is made, the better data and sample will be got.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 광학 및 양자전자학 워크샵
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• pp.41-46
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• 1991

A block quantized binary phase hologram is introduced for optical interconnection and encoded with a simulated alogorithm to achieve high diffraction efficiency and superession of unwanted spots. The block quantized binary phase holograms encoded with the algorithm are fabricated with electron beam lithography and chemical etching. the fabricated holograms showed excellent perfoemances for optical interconnection.

• 마이크로전자및패키징학회지
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• 제19권2호
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• pp.47-53
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• 2012

최근 정보전송량이 증대됨에 따라 PCB는 고속 정보전송 및 박형화가 요구되고 있다. 하지만 기존의 전기적 PCB는 EMI, 실장밀도 등의 문제로 고속전송에 한계가 있어 기존의 전기 회로층에 광 회로층을 접목한 광 PCB가 그 해결책으로 대두되고 있다. 광 PCB 구현에서 가장 중요한 요소는 광 접속기술로 고효율, 수동정렬에 관한 연구가 활발히 이루어지고 있다. 따라서 본 논문에서는 광도파로에 렌즈를 일체형으로 제작하고 이를 보호하는 구조물을 정렬키로 사용한 장착형 광도파로 구조를 제안하였고, 광 및 구조 시뮬레이션을 통해 제안한 구조의 접속효율 및 구조적 안정성을 해석하였다. 광 시뮬레이션 결과 제안된 구조는 렌즈가 없는 구조와 비교해 송신부에서 약 1.86배, 수신부에서 약 1.42배의 높은 접속효율을 가지며, 구조 해석에서는 탈착과정에서 내부의 렌즈에 응력 및 변형이 발생하지 않음을 확인하였다. 따라서 본 논문에서 제안된 구조가 높은 접속효율을 가지고, 구조적 안정성을 가짐을 보였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권1호
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• pp.663-666
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• 2007

High-efficiency red phosphorescent OLEDs employing a novel red emitter and a multifunctional oligofluorene host are reported. With qazIr(acac) as the red phosphorescent dopant, a maximum external quantum efficiency of 19% and maximum power efficiency of 11 lm/W are achieved. In addition, single layer devices using such host and dopant materials have efficiencies up to 13%.

• 한국전기전자재료학회논문지
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• 제21권2호
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• pp.173-177
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• 2008

We have developed the transparent passivation layer for top emission organic light emitting diodes using CsCl thin film by the thermal evaporation method. The CsCl film was deposited on the Ca/Ag semitransparent cathode. The optical transmittance of Ca/ Ag/CsCl triple layer is higher than that of Ca/Ag double layer in the visible range. The device with a structure of glass/Ni/2-TNATA/a-NPD/Alq3:C545T/BCP/Alq3/Ca/Ag/CsCl results in higher efficiency than the device without CsCl passivation layer. The device without CsCl thin film shows a current efficiency of 7 cd/A, whereas the device passivated with CsCl layer shows an efficiency of 10 cd/A. This increase of efficiency isresulted from the increased optical extraction by the CsCl passivation layer.

• Journal of the Optical Society of Korea
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• 제18권1호
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• pp.9-14
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• 2014

We numerically investigate the effect of sunlight polarization on the absorption efficiency of V-shaped organic solar cells (VOSCs) using the finite element method (FEM). The spectral distribution of absorbance and the spatial distribution of power dissipation are calculated as a function of the folding angle for s-and p-polarized light. The absorption enhancement caused by the light-trapping effect was more pronounced for s-polarized light at folding angles smaller than $20^{\circ}$, where s-polarized light has a relatively larger reflectance than p-polarized light. On the other hand, the absorption efficiency for p-polarized light is relatively larger for folding angles larger than $20^{\circ}$, where the smaller reflectance at the interface of the VOSC is more important in obtaining high absorption efficiency.