• 한국전기전자재료학회논문지
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• 제28권2호
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• pp.142-147
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• 2015

The artificial light sources for growth of plant are usually high-pressure sodium lamp, metal haloids lamp, and fluorescent light; however, these light sources have relatively weaker Red and Blue lights that are necessary for growth of plants. Especially the effect of Photosynthetic Photon Flux Density (PPFD) is pointed out as the weakness. Meanwhile, LED light source can be selected by specific wavelength to greatly improve the effect of PPFD. In this regard, this paper aims to investigate the promotion of plant growth by measuring photosynthetic photon flux density (hereafter referred to as PPFD) according to changes in light quality of the LED light sources. Towards this end, LED light sources for plant growth were produced with 4 kinds of mono-chromatic lights and 6 kinds of combined lights by mixing red, blue, green and white lights. A comparative analysis was conducted to investigate the effects of optical properties and PPFD on plants (green leaf lettuce) using the produced light sources. The results monochromatic light has fastest growth rate, but plant growth conditions have poor. This being so, mixed light is suitable for the green leaf lettuce.

• Journal of Mechanical Science and Technology
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• 제15권3호
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• pp.309-319
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• 2001

This paper demonstrates the development of optical temperature sensor based on the etched silica-based planar waveguide Bragg grating. Topics include design and fabrication of the etched planar waveguide Bragg grating optical temperature sensor. The typical bandwidth and reflectivity of the surface etched grating has been ∼0.2nm and ∼9%, respectively, at a wavelength of ∼1552nm. The temperature-induced wavelength change is found to be slightly non-linear over ∼200$^{\circ}C$ temperature range. Typically, the temperature-induced fractional Bragg wavelength shift measured in this experiment is 0.0132nm/$^{\circ}C$ with linear curve fit. Theoretical models with nonlinear temperature effect for the grating response based on waveguide and plate deformation theories agree with experiments to within acceptable tolerance.

• Applied Science and Convergence Technology
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• 제26권4호
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• pp.91-94
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• 2017

AThe effect of localized surface plasmon on silicon substrates was studied using silver nanoparticles. The nanoparticles were formed by self-arrangement through the surface energy using rapid thermal annealing (RTA) technique after the thin nanolayer of silver was deposited by thermal evaporation. By the theoretical calculation based on Mie scattering and dielectric function of air, indium tin oxide (ITO), and silver, the strong peak of scattering cross section of silver nanoparticles was found at 358 nm for air, and 460 nm for ITO, respectively. Accordingly, the strong suppression of reflectance under the condition of induced light of $30^{\circ}$ occurred at the specific wavelength which is almost in accordance with peak of scattering cross section. When the external quantum efficiency was measured using silicon solar cells with silver nanoparticles, there was small enhancement peak near the 460 nm wavelength in which the light was resonated between silver nanoparticles and ITO.

• 한국전기전자재료학회논문지
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• 제22권12호
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• pp.1045-1057
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• 2009

The authors investigated the InGaN/GaN multi-quantum well blue light emitting devices with the implementation of the photonic crystals fabricated at the top surface of p-GaN layer and the bottom interface of n-GaN layer. The top photonic crystals result in the lattice-dependent photoluminescence spectra at the wavelength of 450 nm and however, the bottom photonic crystal shows a big shift of the photoluminescence peak from 444 nm to 394 nm. The sample with the bottom photonic crystal structure also shows the lasing effect at the wavelength of 468 nm. Furthermore, the quality enhancement for the crystal growth of GaN thin film on the bottom photonic crystal comes from the modulated compressive stress which was measured by the micro-Raman spectroscopy.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2017년도 춘계학술대회
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• pp.712-713
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• 2017

발광 다이오드는 임상용으로 사용되는 레이저에 비해서 발생하는 열이 적고, 일반 건강한 세포에 무해하며, 비침습적인 특성으로 높은 안전성을 가지고 있으며 현재 많은 연구가 진행되고 있다. 따라서 본 논문에서는 복수의 파장대역을 갖는 발광 다이오드를 이용하여 사람의 자궁경부암 조직의 증식억제 주파수효과를 확인하였다. 준비된 자궁경부암 세포를 다양한 파장대의 발광 다이오드에 일정한 시간동안 조사한 후 세포의 활성도를 측정하였고, 그 결과 비교적 파장이 긴 빨강과 초록색의 노출보다 파장이 짧은 파란색 빛이 자궁경부암 세포의 증식억제 효과가 있음을 확인하였다.

• Transactions on Electrical and Electronic Materials
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• 제11권6호
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• pp.279-284
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• 2010

This study has been carried out to determine the optimal process conditions of $AZO:H_2$ thin films for the maximization of the transmittance of a blue GaN light-emitting diode (LED) with a wavelength of 470 nm. The Al-doped zinc oxide $(AZO):H_2$ thin films were deposited on a sapphire substrate by radio-frequency magnetron sputtering system with varying substrate temperatures, working pressures and annealing temperatures temperature, working pressure and annealing imposed on a AZO (2wt% $Al_2O_3$) ceramic target. The effect of these variables was investigated in order to improve the light extraction efficiency of the LED. As a result, the (002)-oriented peak was found in all the $AZO:H_2$ thin films. The lowest resistivity and the best transmittance at a wavelength of 470 nm was found to be $4.774\;{\times}\;10^{-4}\;{\Omega}cm$ and 92% at a substrate temperature of $500^{\circ}C$, working pressure of 7 mTorr and annealing temperature of $400^{\circ}C$. The transmittance of the $AZO:H_2$ thin film for the Blue GaN LED was improved by approximately 13% relative to that of a ITO thin film (T = 79%).

• 한국버섯학회지
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• 제11권4호
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• pp.226-229
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• 2013

표고 톱밥재배시 LED광파장에 따른 생육특성을 분석한 결과, 파장이 긴 적색광과 황색광에서 대길이가 길어지고 갓색이 연해지며, 파장이 짧은 청색광과 녹색광에서는 대길이가 짧아지고 갓색이 진해지는 현상을 보였다. 자실체 항산화활성은 광파장에 따른 큰 차이를 보이지 않았으며, 2주기까지 배지당 자실체 수량은 녹색에서 159 g으로 형광등 121 g 대비 31% 증수효과가 있었다.

• Medical Lasers
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• 제10권2호
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• pp.82-89
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• 2021

Background and Objectives Due to changes in diet and lifestyle, the number of obese people worldwide is steadily increasing. Obesity has an adverse effect on a healthy life, so it needs treatment and improvement. Research related to this is continuously being conducted. Materials and Methods The laser system to compact designed using 808 nm laser diode and Neodymium Yttrium orthovanadate generates a 1064 nm wavelength, the periodically polarized nonlinear crystal pumping laser beam. The pulsed 1064 nm wavelength beam passing through the AO Q-switch is used as the pumping light of the nonlinear optical crystal and is irradiated to the periodic polarized nonlinear optical crystal with a quasi-phase matching period. Nonlinear optical crystals use an oven to control the temperature to generate the desired 1980 nm and 2300 nm wavelengths. Results The 1980 nm and 2300 nm wavelengths generated by temperature control of nonlinear optical crystals are effective for lipolysis. A fiber catheter was used so that the laser could be directly irradiated to the fat cells. In particular, the new wavelength (1980 nm, 2300 nm) can increase the fat reduction effect with low energy (1.3 W). When a laser with a combination wavelength of 1980 nm and 2300 nm was used, an average lipolysis effect of 20% was obtained. Conclusion A mid-infrared lipolysis laser system with excellent absorption of fat and water has been developed. We conducted a princlinical study to confirm the efficacy and safety of the lipolysis laser system, and obtained good results for lipolysis with low energy.

• 현장농수산연구지
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• 제22권1호
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• pp.99-112
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• 2020

LED 광원이 느티만가닥버섯 재배에 미치는 영향을 알기 위하여 6종의 파장이 다른 NUV(wave length 405nm), blue(wave length 460nm), green(wave length 530nm), yellow(wave length 590 nm), red(wave length 630nm), white(wave length 6500K) 광을 조사하면서 균사 생장 및 자실체 생육과 수량을 조사하였다. 1. 느티만가닥버섯균의 균사 생장에는 광이 필요하지 않지만, red 광 처리구에서 암조건과 비슷한 균사 생장을 보였다. 그러나 blue, green, yellow 광 처리구에서는 암배양보다 약 30~40%의 균사 생장 저해를 보였다. 2. LED 광이 느티만가닥버섯의 자실체 생육에 미치는 영향을 조사한 결과, 암조건에서는 자실체 발달이 안 되는 경우도 있으므로, 느티만가닥버섯의 자실체 생육에는 광 조사가 꼭 필요하다. 단파장인 blue와 green광, 복합광인 white을 조사한 처리구에서 자실체 갓과 대 발달이 안정적이면서 수량이 우수하였다. 장파장인 red 와 yellow 광 처리구에서는 갓 발달과 색택이 불량하고, 대는 길고 꼬임 등의 기형을 보였다. 3. 단일광 조사만으로는 우수한 품질의 버섯을 안정적으로 생산하기 어렵고, 각 생육 단계마다 효과가 있는 광을 조사하는 것도 어렵다. blue와 green, white, red 광을 조합하여 생육 기간 동안 혼합광을 조사하여 갓과 대의 균일성 및 갓 색택, 수량을 분석한 결과, 가장 이상적인 LED 광 조합은 blue와 white 광이었다.

• 한국정보통신학회논문지
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• 제25권2호
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• pp.221-227
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• 2021

최근 발광다이오드를 이용한 마스크 형식의 피부 관리기에 관한 관심이 증가하고 있으며, 특정 파장의 광학적 자극은 노출 광량 및 파장대, 광선 조사 시간을 조절함으로써, 피부 미백, 여드름 치료, 탄력 및 주름 개선 등과 같은 다양한 효과를 보인다고 알려져 왔다. 특히, 피부 노화 억제, 세포증식 유도, 피부의 염증 완화 등을 목적으로 하는 마스크의 경우 각각 다른 파장의 광원이 사용된다. 본 논문에서는 마이크로컨트롤러를 사용하여 피부재생 마스크에 활발하게 사용되는 발광다이오드 제어시스템을 개발하였다. 단일 또는 복합적으로 피부 섬유아세포에 인가하여, 세포의 증식에 어떠한 효과가 있는지 확인한다. 또한, 세포증식률에 긍정적 효과를 보이는 특정 파장대를 찾아 다양한 자극에 기인한 세포증식 효과를 확인하고, 영상처리를 활용한 정량분석법을 제시하여 그 효과를 평가하였다.