• Journal of Information Display
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• 제5권1호
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• pp.7-15
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• 2004

A highly simplified backlight unit mainly composed of diffractive grating in sub-micron order imprinted light-guide plate (LGP) is proposed for edge-lit backlight unit. Optical characteristics of the imprinted LGP are examined by RCWA and the performance is verified through Monte Carlo simulation. Results show that the diffraction efficiency, luminous flux and its uniformity over the area are significantly affected by the angle of incident ray. Consequently couples of design considerations are additionally proposed to enhance luminous flux. In terms of peak luminance and out-coupling luminous flux, the experimental results are agreed well with the performance simulation. Finally, compared with optical characteristics of conventional backlight unit, we could conclude that the proposed simplified backlight unit made of diffractive grating imprinted light-guide plate is a good substitute for the conventional backlight unit.

• Journal of the Optical Society of Korea
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• 제18권2호
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• pp.180-183
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• 2014

The surface of semiconductor solar cells, such as a-Si or CIGS (CuInGaSe) solar cells is not flat but textured in the microscopic domain. With textured surfaces, the optical reflectivity of a solar cell is different from that of flat surfaces in the wavelength region. In this paper, the effects of a textured surface on a CIGS solar cell are presented by RCWA (Rigorous Coupled Wave Analysis) method. The effect of incoherent light is also considered by RCWA with a Fourier analysis while conventional optical simulation uses the input light on the solar cell as coherent light. Using experimental results, the author showed that the RCWA method with a Fourier analysis is a proper method to simulate the optical properties of CIGS solar cells.

• 한국정보기술학회 영문논문지
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• 제8권2호
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• pp.147-157
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• 2018

In this study, we analyzed an outdoor visible light communication system and implemented it through a simulation. We designed a Reed-Solomon encoder, a variable interleaver structure, and set it to the Institute of Electrical and Electronics Engineers (IEEE) 802.15.7 PHY I specification mode. We also analyzed the performance of an additive white gaussian noise (AWGN) channel environment using a root-raised-cosine (RRC) filter, implemented a MATLAB simulation and analyzed its performance. The results showed a requirement for an additional signal-to-noise ratio (SNR) of approximately 1.5 dB in a 3-ray multipath visible light channel environment than in an AWGN environment.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume I
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• pp.274-277
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• 2006

KARI is currently developing a geostationary ocean color imager (GOCI) for COMS. We report the progress in integrated optical modeling and analysis for stray light suppression and the end-to-end instrument performance verification including in-orbit calibration. The Sun is modeled as the emitting light source and the selected area around Korean peninsular as the observation target that scatters the sun light towards GOCI in orbit. The optical ray tracing employing active geometric scaling was then used for precise characterization of the spatial and radiometric performance at the instrument focal plane. The analysis results show positive reduction in the simulated stray light level with the design improvement including baffles. It also indicates that the ray traced in-orbit radiometric performances are effective tools for the independent assessment of more traditional linear and quadratic equation based estimation of water leaving radiance. The concept of integrated GOCI optical model and the computational method are presented.

• 조명전기설비학회논문지
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• 제24권5호
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• pp.77-85
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• 2010

본 논문은 LED 램프를 사무소 건물에 효과적으로 사용하기 위하여 새로운 통합적 에너지 시뮬레이션을 수행한 연구 결과이다. 일반적으로 LED 램프는 다른 램프에 비하여 에너지 절감효과가 매우 우수하지만 현재 형광램프보다 낮은 광속과 좁은 광분포 등 아직 사무소 건물에 적용하기는 다각적인 검토가 필요하다. 연구결과 냉난방에너지가 20[%] 증가하고 현재 형광등을 대체하기 위해서는 90[lm/$m^2$] 이상으로 설계해야 한다. 따라서 LED램프를 사무소 건물에 적용하기 위해서 광에너지, 냉난방에 미치는 영향 및 사무실환경에 미치는 광분포를 통합적으로 해석하였으며 앞으로 이 결과는 LED 램프를 통한 효과적인 에너지절약 환경을 구축하는 데 중요한 자료를 제공할 것으로 확신한다.

• 조명전기설비학회논문지
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• 제22권8호
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• pp.1-11
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• 2008

본 논문의 목적은 광선반을 사무소건물에 효율적으로 적용할 수 있는 기준자료를 제시하는 것이다. 광선반의 채광성능 시뮬레이션을 위해 3Ds Studio Max 프로그램이 사용되었으며, 광선반의 폭, 표면반사율, 설치각도와 같은 주요 변수의 최적값을 도출하였다. 다음으로 이러한 최적값을 이용하여 광선반의 채광성능을 분석하였다. 시뮬레이션 결과 사무소건물에서 광선반을 설치함으로써 주광성능을 향상시킬 수 있는 것으로 나타났다.

• 한국표면공학회지
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• 제47권5호
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• pp.233-238
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• 2014

In this paper, in order to achieve slim and light liquid crystal display, we examine the optical conditions that can obtain uniform light with higher optical efficiency over whole light guide plate (LGP) through simulation. Furthermore, to overcome the issues of hot spot in front of red, green, and blue light emitting diodes (RGB LEDs) source and non-uniform color mixing, we propose four shaped color mixing bars tied up with the LGP and check the optical characteristics of the LGP with them by simulation. Consequently, we could know the optical conditions of improving optical efficiency and optical uniformity in the LGP through the optical design. Also we confirmed that the issues of the hot spot and non-uniform color mixing in edge type LED could be solved by using the ${\bigwedge}$-shaped window color mixing bar.

• KIEAE Journal
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• 제11권6호
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• pp.71-79
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• 2011

There are high recognitions on the importance of comforts in Elderly living environment, but the circumstance is that studies on seniors facility space itself are approached only in planning level, and studies on lighting environment which is significantly associated with the comfort in the indoor environment of seniors where they actually spend the majority of their time are not that active. This study was intended to deduce cozy bedroom environment to which existing elderly care facility can be improved by using light shelf the lighting system with the advantage of being able to serve both as building sun visor and lighting window simultaneously in order to analyze the interior environment of bedroom space of elderly care facility the indoor space where the aged spend the majority of their life and examine the directions for the improvement of existing building lighting system through remodeling and renovation. In this study, lighting performance analysis was done in a way that the windows of the bedroom unit in existing facility were set in southbound direction based on two standard types and were put under initial simulation with the use of Autodesk Revit 2011, and after the simulation results were converted to Green Building Studio gbXML file to be used in ECOTECT, Daylight Autonomy a dynamic simulation and static natural lighting simulation the existing method of calculating daylight factors were deduced through Ecotect Analysis 2011. In conclusion, exiting standard model was found in such a condition that the daylight factors for both type A and type B were above 5% the proper standard value, and required improvement. In case light shelf the natural lighting system was attached, the daylight factor was improved to proper standard value for type A, and also was improved above existing facility for type B.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.46-47
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• 2008

Organic light-emitting diode is quick response speed, low power consumption and the self-interest has many advantages, such as insanity. So, organic light-emitting diode mechanism of light-emitting diode in order to more clearly understand the changes in the thickness of emitting materials for OLED characteristics of the simulation. emitting layer to a thickness of 10 [nm] ~ 100 [nm] changed the experiment, and hole transport layer 190 [nm] as a fixed. and emitting layer 10 [nm] ~ 100 [nm] to change the simulation results. Changes in the thickness of emitting layer gradually increased. depending on the emitting was 20 [nm] in the high 441 [lm / W] shows. and was gradually reduced. emitting layer 190 [nm] when fixed, hole transport layer, depending on changes in the thickness of 70 [nm] in the efficiency maximum value of 477 [lm / W], and was gradually reduced.

• Journal of the Optical Society of Korea
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• 제17권3호
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• pp.269-274
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• 2013

The effect of diffusing substrate and pillow lenses on the outcoupling efficiency of organic light-emitting diodes (OLEDs) was studied by optical simulation based on the point-dipole model. The diffusing substrate included Mie scatterers by which the condition of total internal reflection could be broken. The finite-difference time-domain method was used to obtain the intensity distribution on the transparent electrode of an OLED, which was used as a light source to carry out a ray-tracing simulation of the OLED and the diffusing substrate. It was found that the outcoupling efficiency of the OLED was sensitive to the thickness of organic layers and could be increased by 21.0% by adopting a diffusing substrate in which Mie scatterers whose radius was $2.0{\mu}m$ were included at the density of $10^7mm^{-3}$ and by 65.5% by forming one pillow lens with the radius of 2 mm on the front surface of the glass substrate. This study revealed that the outcoupling efficiency could be improved by adopting diffusing substrate and pillow lenses along with the optimization of the thickness of each layer in the OLED.