• 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%).

• Journal of the Korean Wood Science and Technology
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• 제48권4호
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• pp.548-561
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• 2020

Paecilomyces japonica is widely cultured to produce mycelium for medicinal and health food use. Illumination is an important factor in the growth and production of mycelium in submerged culture. The effects of different light-emitting diode (LED) combinations on the growth and cordycepin content as bioactive substances of mycelium were investigated. The results showed that the mycelium dry weights were lower under dark condition and red LED treatments. Dark condition, fluorescent light, and ultraviolet-A failed to increase the cordycepin content. Blue light was necessary to increase the cordycepin content, and a red-to-blue ratio of 3:7 induced the highest cordycepin content. The cordycepin contents of mycelium in submerged culture were significantly higher in a 12 h/day illumination time under red and blue (red-to-blue ratio of 3:7) LED treatments, showing an increase of up to 38% compared with those under the fluorescent-light control condition. The results demonstrated the roles of light with different wavelengths on the biosynthesis of cordycepin as bioactive substances. The low-heat release and replacement of traditional fluorescent lights with low-energy-consuming LEDs could increase the contents of bioactive substances. After optimization of the cordycepin production using response surface methodology (Box-Behnken design) to its canonical form, the optimum combination was found to be as follows: illumination time = 17.7 h/day, sugar content in the medium = 9.7 g/50 mL, and incubation time = 61.2 h. The model predicted a maximum response of 3779.2 ㎍/mL cordycepin yield.

• Animal Bioscience
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• 제36권5호
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• pp.731-739
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• 2023

Objective: This study was to evaluate the interaction of three different light-emitting diode (LED) light colors (white, green, and blue) and three intensities (5, 10, and 15 lx) on slaughter performance, meat quality and serum antioxidant capacity of broilers raised in three-layer cages. Methods: A total of 648 (8-days-old) male broiler chicks (Cobb-500) were randomly assigned in 3×3 factorially arranged treatments: three light colors (specifically, white, blue, and green) and three light intensities (namely, 5, 10, and 15 lx) for 35 days. Each treatment consisted of 6 replicates of 12 chicks. The test lasted for 35 days. Results: The semi-eviscerated weight percentage (SEWP) in 5 lx white was higher than that in 15 lx (p<0.01). The eviscerated weight percentage (EWP) (p<0.05) and water-loss percentage (WLP) (p<0.01) decreased in 10 lx white light than those in green light. Under blue light, the content of hypoxanthine (Hx) in muscle was lower than that under white and green light (p<0.01). The content of malondialdehyde (MDA) in 15 lx blue light was higher than that in 10 lx green light (p<0.05). Light color had an extremely significant effect on thigh muscle percentage, WLP, Hx, and crude protein content (p<0.01). Light intensity had a significant effect on SEWP (p<0.05), EWP (p<0.05), lightness (L^*) value (p<0.05), WLP (p<0.01), and the contents of superoxide dismutase (p<0.05), MDA (p<0.01), glutathione peroxidase (p<0.01). Conclusion: Using white LED light with 10 lx light intensity can significantly improve the chicken quality of caged Cobb broilers, improve the content of inosine acid in chicken breast and enhance the antioxidant capacity of the body. We suggest that the broiler farm can use 10 lx white LED light source for lighting in 8 to 42 days.

• Journal of Biosystems Engineering
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• 제38권4호
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• pp.318-326
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• 2013

Purpose: We developed a viability evaluation method for cucumber (Cucumis sativus) seed using hyperspectral reflectance imaging. Methods: Reflectance spectra of cucumber seeds in the 400 to 1000 nm range were collected from hyperspectral reflectance images obtained using blue, green, and red LED illumination. A partial least squares-discriminant analysis (PLS-DA) was developed to predict viable and non-viable seeds. Various ranges of spectra induced by four types of LEDs (Blue, Green, Red, and RGB) were investigated to develop the classification models. Results: PLS-DA models for spectra in the 600 to 700 nm range showed 98.5% discrimination accuracy for both viable and non-viable seeds. Using images based on the PLS-DA model, the discrimination accuracy for viable and non-viable seeds was 100% and 99%, respectively Conclusions: Hyperspectral reflectance images made using LED light can be used to select high quality cucumber seeds.

• 생물환경조절학회지
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• 제27권1호
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• pp.54-63
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• 2018

적색과 청색광은 식물의 광합성에 효과적인 파장으로 알려져 있다. 본 연구는 다양한 조합의 적색과 청색 LED 혼합광에서 자란 방울 토마토 묘의 생장과 정식 후의 생산량과 품질에 대한 영향을 구명하였다. 파종 후 2주된 방울 토마토 묘(Solanum lycopersicum L. cv. 'Cuty')를 적색(655nm)과 청색(456nm) LED의 다양한 비율의 혼합광[red:blue = 41:59 (59B), 53:47 (47B), 65:35 (35B), 74:26 (26B), 87:13 (13B), or 100:0(0B)]과 형광등(대조구)이 설치된 생장상에 옮겨준 후 $25/20^{\circ}C$ (주/야), 광합성 광량자속 $198.6{\pm}5{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ (12시간)의 조건에서 27일간 육묘하였다. 그 후 방울 토마토를 벤로형 온실에 정식하여 75일동안 재배하였다. 정식 전 육묘 단계에서 27일간 LED 처리된 0B 와 59B 처리구를 제외한 모든 RB 혼합광 처리의 지상부 생체중이 대조구에 비해 높았다. 지상부 건물중과 엽면적 또한 지상부 생체중과 유사한 경향을 보였다. 줄기 신장은 13B, 26B, 35B에서 대조구와 다른 처리구들에 비해 유의적으로 가장 높았다. 특히, 26B는 59B처리에 비해 약 3.2배 높은 줄기 신장을 보였다. 정식 후 37일 째에 마딧수는 26B와 47B에서 유의적으로 가장 높았고, 식물 초장은 26B에서 대조구와 59B에 비해 유의적으로 높았다. 가장 높은 총 과실 생산량을 보였던 26B는 대조구에 비해 1.6배, 59B에 비해 1.8배 높은 총 과실 생산량을 보였다. 따라서, 본 연구는 적색과 청색 LED의 다양한 혼합 비율이 방울 토마토 묘의 생장 및 발달과 정식 후의 과실 생산량과 같은 생식생장에 영향에 중요한 요소임을 제시한다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1992년도 제3회 학술발표회 논문개요집
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• pp.7-7
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• 1992

• 한국응용과학기술학회지
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• 제39권4호
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• pp.552-559
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• 2022

아토피 피부염(Atopic dermatitis, AD)은 주로 5세 이전에 발병하여 심한 가려움을 동반하는 만성 염증성 피부질환이다. 본 연구의 목적은 NC/Nga 마우스를 AD 유사 증상에 대한 405 nm+ 850 nm LED 광선 치료의 효과를 조사하는 것이다. 마우스는 Normal (Vehicle), 아토피성 피부염 유발군 (CON), 405 nm+ 850 nm LED 광선 치료군 (LED)으로 나누어 난괴법을 이용하여 무작위 배치하여 실험을 진행하였다. LED 실험군은 하루 10분씩 405 nm+ 850 nm 파장의 LED 치료를 7일 간 실시하였다. LED 광선치료 연구는 Dermatics 점수의 개선을 측정하고 피부염으로 인한 표피조직 두께 감소를 관찰하였다. LED 광선 요법으로 인한 혈청 IL-1𝛽의 현저한 감소와 경피 수분 손실 및 혈청 IgE 농도 결과를 바탕으로 LED 광선 치료는 아토피 유발 생쥐의 정상적인 피부 상태 회복에 도움을 주었다. 본 연구 결과는 아토피 피부염 마우스 모델에서 적외선 영역의 광선과 blue light 영역의 광선의 동시 조사치료가 아토피 피부염 치료에 뛰어난 효능을 가지며, 두 파장의 LED의 동시 사용 가능성에 대하여 시사하였다.

• Animal Bioscience
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• 제34권11호
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• pp.1870-1878
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• 2021

Objective: The objective of this experiment was to investigate the effects of different colors produced by light emitting diode (LED) on Brown Tsaiya ducks. Methods: A total of 144 female Brown Tsaiya ducks were randomly allocated into three individual cage rearing chambers with different LED illumination colors as treatments. Three different treatments were: i) white color, ii) blue color, and iii) red color. The experiment periods were from ducks 21 to 49 weeks of age, determined traits included i) egg laying performance, ii) feed intake, iii) egg shell breaking strength, iv) egg shell thickness, v) egg Haugh unit, vi) egg weight, vii) serum Estradiol and Progesterone concentration, and viii) behavior pattern. Results: The results indicated that when compared with white and blue color, red color could stimulate ducks sexual maturation and raised the egg laying performance. The red light group was also observed to have the highest feed intake among three treatments. The blue treatment had the lowest egg shell breaking strength and the highest egg weight among three treatments, nevertheless, no significant difference was observed among three treatments on egg shell thickness and egg Haugh unit. The red light group had higher serum estradiol concentration than the white and blue groups, but no significant difference among treatments on the serum Progesterone concentration was found. The results of behavior pattern indicated that red light group showed more feeding and less resting behavior compared to the blue light group. Conclusion: We found a potential of applying red light illumination in the indoor laying duck raising system with positive results on egg laying performance and acceptable egg weight, equivalent egg qualities compared to white and blue light.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 1999년도 학술대회논문집-국제 전기방전 및 플라즈마 심포지엄 Proceedings of 1999 KIIEE Annual Conference-International Symposium of Electrical Discharge and Plasma
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• pp.213-216
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• 1999

빛의 3원색 Red, Green, Blue를 조합하여 분광조성을 달리하면 원하는 광색을 낼 수 있다. 이를 하나의 광원 형태로 개발하면 응용의 폭이 넓다는 장점을 지닌다. 현재 개발된 LED와 마이크로프로세서 기술은 이와 같은 가변색 광원을 만들기에 가장 적당한 것들이라고 판단하여 LED를 이용한 가변색 광원을 연구, 시제품을 제작하였다. 그리고, 개발된 가변색 광원의 응용분야와 가능성, 거기에서 파생될 수 있는 문제점을 분석하여 제시하였다.

• Journal of Information Display
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• 제10권4호
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• pp.164-170
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• 2009

The dependences of color gamut size and power consumption on the area ratio of the neutral and green subpixels for the RGB-LED-backlight RGBW LCD were studied, in which the red- and blue-subpixel areas are the same and represent one-quarter of the pixel aperture area. It was found that the color saturation of the RGBW LCD can be improved through the use of a smaller neutral- and green-subpixel area ratio, at the expense of higher power consumption.