• 한국광학회지
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• 제28권6호
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• pp.273-280
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• 2017

본 논문에서는 낮은 도로 조명을 위한 freeform reflector를 설계하였다. 높이에 비해 넓은 차선까지 배광을 보내야 하는 낮은 도로 조명의 경우, 기존의 등주식 도로 조명에 비해 균제도를 맞추기 힘들다는 단점이 있다. 조명 등급 M3를 만족시키기 위해 reflector를 part 9개로 나누어 part 별 반사면의 기울기를 변화시켜 원하는 배광을 갖도록 하였고, 각 점을 기준으로 fitted curve를 그려 이에 따른 수식을 도출하였다. LightTools의 street light simulation을 통해 M3 조명 등급에 만족하는 것을 확인하였고 직접 제작하여 실제 도로상에서 조명 등급을 만족시키며 설계 결과에 대한 타당성을 입증하였다.

• 한국광학회지
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• 제29권6호
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• pp.233-240
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• 2018

본 논문에서는 불꽃감지기용 테스트램프의 반사경 형상에 대해 제작 시 오차를 줄일 수 있는 설계 방법 연구를 진행하였다. 테스트램프는 높은 광량의 빛을 평행하게 진행시켜야 하지만, 제작 시 중앙 빛을 제어하는 소형 반사경의 고정이 어렵다는 단점으로 인해 광량 저하가 발생하여 목표 광량을 만족하지 못하는 경우가 많다. 이러한 문제점 해결을 위해 틸트 및 디센터 시에도 성능 저하 현상을 최소화하는 방향으로 광 손실률 5% 미만의 구 소형 반사경 설계를 진행하였고, 설계 분석 결과에 따라 광학계 제작 시에도 오차 영향이 적은 소형 반사경으로 구체 형상을 제시하였다.

• 한국광학회지
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• 제30권5호
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• pp.197-203
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• 2019

본 논문은 광 소결 공정에 쓰이는 제논 플래시 램프 사용 시 조도 균일도를 개선시킬 수 있는 반사경 설계에 대한 연구를 진행하였다. 조사 영역에서 기판의 완전한 소결이 이루어지기 위해서 광효율과 조도 균일도를 목표 성능으로 설정하였다. 기존의 타원 반사경 또는 포물 반사경을 이용한 방식은 광효율을 만족하기 용이하지만 조도 균일도를 만족하는데 어려움이 있다. 따라서 본 논문에서는 조도 균일도를 만족시키기 위해 포물경의 중앙부에 쌍오목 형상을 추가하였다. 이러한 쌍오목 형태의 중앙부 형상을 갖는 포물 반사경의 조도 균일도가 기존의 반사경에 비해 향상됨을 확인하였다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2009년도 9th International Meeting on Information Display
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• pp.614-615
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• 2009

For the high reflectance under the ambient light condition, a highly efficient diffractive reflector has been proposed, based on a micro grating structure.[1] This reflector was designed to show highly concentrated distribution of the reflected light to the normal direction of the reflector under specific incident conditions of the light. In order to apply a diffractive reflector to a reflective liquid crystal display, the coupling between the viewing angle characteristics of a liquid crystal (LC) cell and the reflective distribution of the reflector should be considered. Under the optimum configuration confirmed through the analysis of the coupling between a LC cell and a reflector, a reflective vertical alignment (VA) cell with a diffractive reflector shows contrast ratio and brightness much higher than that with a conventional bumpy reflector.

• 한국광학회지
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• 제29권6호
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• pp.253-261
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• 2018

본 논문은 비대칭 배광을 가지는 LED 광원용 반사경 설계 방법에 대한 연구를 진행하였다. 스포츠 경기에서 광원을 중심으로 대칭 배광을 갖는 조명은 선수와 관중이 광원을 직접적으로 바라보게 되어 눈부심을 발생시키는 문제점이 있다. 이러한 문제점을 해결하기 위해 최적 기울기 각도를 도출하여 비대칭 배광을 갖는 반사경 설계를 진행하였다. 이후 테니스장 조명 규격에 맞게 배치하여 성능 분석을 진행하였고 유럽 표준 조명 등급의 Class 1을 만족하는 것을 확인하였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.251-252
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• 2012

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low Water Vapor Transition Rate (WVTR) of $1{\times}10^{-6}g/m^2$/day. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2$/day) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study, we developed an $Al_2O_3$ nano-crystal structure single gas barrier layer using a Neutral Beam Assisted Sputtering (NBAS) process. The NBAS system is based on the conventional RF magnetron sputtering and neutral beam source. The neutral beam source consists of an electron cyclotron Resonance (ECR) plasma source and metal reflector. The Ar+ ions in the ECR plasma are accelerated in the plasma sheath between the plasma and reflector, which are then neutralized by Auger neutralization. The neutral beam energies were possible to estimate indirectly through previous experiments and binary collision model. The accelerating potential is the sum of the plasma potential and reflector bias. In previous experiments, while adjusting the reflector bias, changes in the plasma density and the plasma potential were not observed. The neutral beam energy is controlled by the metal reflector bias. The NBAS process can continuously change crystalline structures from an amorphous phase to nano-crystal phase of various grain sizes within a single inorganic thin film. These NBAS process effects can lead to the formation of a nano-crystal structure barrier layer which effectively limits gas diffusion through the pathways between grain boundaries. Our results verify the nano-crystal structure of the NBAS processed $Al_2O_3$ single gas barrier layer through dielectric constant measurement, break down field measurement, and TEM analysis. Finally, the WVTR of $Al_2O_3$ nano-crystal structure single gas barrier layer was measured to be under $5{\times}10^{-6}g/m^2$/day therefore we can confirm that NBAS processed $Al_2O_3$ nano-crystal structure single gas barrier layer is suitable for OLED application.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.52-52
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• 2011

A novel deposition process for n-type nanocrystalline silicon (n-type nc-Si) thin films at room temperature has been developed by adopting the neutral beam assisted chemical vapor deposition (NBa-CVD). During formation of n-type nc-Si thin film by the NBa-CVD process with silicon reflector electrode at room temperature, the energetic particles could induce enhance doping efficiency and crystalline phase in polymorphous-Si thin films without additional heating on substrate; The dark conductivity and substrate temperature of P-doped polymorphous~nano crystalline silicon thin films increased with increasing the reflector bias. The NB energy heating substrate(but lower than $80^{\circ}C$ and increase doping efficiency. This low temperature processed doped nano-crystalline can address key problem in applications from flexible display backplane thin film transistor to flexible solar cell.

• 한국생산제조학회지
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• 제22권3호
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• pp.480-487
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• 2013

In this study, we researched the LED source MR16,which maintains the strong points of an ordinary MR16 while compensating for its weak points. The optical system composition of the LED MR16 includes four aspherical lens per sheet and a patterned reflector. The aspherical optical system and reflector were designed using optical software, and the performance was estimated using a lighting simulation program. Finally, a prototype was manufactured after analyzing the simulation data, and the reliability of the simulation results was estimated using a comparative analysis of the designed data and measured data.

• 반도체디스플레이기술학회지
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• 제22권4호
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• pp.103-107
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• 2023

To solve the reliability problem of organic devices that are often used outdoors, multifunctional gas barriers that block reactive gases such as moisture and oxygen and reflect harmful light such as ultraviolet rays are needed. In this study, ALD nanolaminate-based optically functional n-DBR was developed to overcome the poor gas permeability of polymer substrates and protect organic devices from harmful light. n-DBR not only achieved a WVTR of 8.76 × 10^-6 g·m^-2·day^-1, but also showed a visible light transmittance of 94.3% and an ultraviolet ray blocking ability of 2.67%. In particular, n-DBR based on a nanolaminate structure maintained its permeability characteristics even in a high temperature and high humidity environment despite being used as a layer of Al₂O₃. This functional barrier Structure can not only be used as a functional encapsulation barrier for the reliability of organic devices, but can also be used as a tinting film for vehicles.

• Advances in nano research
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• 제13권5호
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• pp.475-485
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• 2022

Crystalline silicon photovoltaic cells have advantages of zero pollution, large scale and high reliability. A major challenge is that sunlight wavelength with photon energy lower than semiconductor band gap is converted into heat and increase its temperature and reduce its conversion efficiency. Traditional cooling PV method is using water flowing below the modules to cool down PV temperature. In this paper, the idea is proposed to reduce the temperature of the module and improve the energy conversion efficiency of the module through the modulation of the solar spectrum. A spectrally selective nanofilm reflector located directly on the surface of PV is designed, which can reflect sunlight wavelength with low photon energy, and even enhance absorption of sunlight wavelength with high photon energy. The results indicate that nanofilm reflector can reduce spectral reflectivity integral from 9.0% to 6.93% in 400~1100 nm wavelength range, and improve spectral reflectivity integral from 23.1% to 78.34% in long wavelength range. The nanofilm reflector can reduce temperature of PV by 4.51℃ and relatively improved energy conversion efficiency of PV by 1.25% when solar irradiance is 1000 W/m². Furthermore, the nanofilm reflector is insensitive in sunlight's angle and polarization state, and be suitable for high irradiance environment.