• 신재생에너지
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• 제5권4호
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• pp.34-37
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• 2009

Using six SMD(surface mount device) type AlGaAs/GaAs single junction solar cells connected in series, a power source was fabricated for a white GaN LED. The electrical properties of the power source was measured and analyzed under one sun (100mW/$cm^2$) and various indoor light (300 - 900 lux) conditions. Under 600 lux indoor light condition, output power was 17.06 ${\mu}W$ and it was 30.75 ${\mu}W$ under 900 lux indoor light condition. Using the fabricated solar cell power supply, we have turned on the white GaN LED. It was worked well under 15 ${\mu}W$(at 480 lux) power supplied from solar cell array. This kind of solar cell power supply can be used as a power source for ubiquitous sensor network (USN).

• 수산해양기술연구
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• 제53권3호
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• pp.211-218
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• 2017

The catch performance of the silver-white jig for automatic jigging machine, developed to improve the effectiveness of LED fishing lamp in catching squid, was compared to that of the conventional green jig. The vessels used in this investigation were Haesong-ho (A-vessel), a training vessel of Gangwon State University and Haengbok-ho (B-vessel), a commercial fishing boat. In the case of the A-vessel, five to eight automatic jigging machines were used in the fishing operation with a 31.3 kW LED fishing lamp in summer. As for the B-vessel, fourteen automatic jigging machines were used with a 43.2 kW LED fishing lamp in autumn and winter. The results showed that the catch performance of the silver-white jig was similar to that of the green jig in the case of the A-vessel (p>0.05). However, in the case of the B-vessel, the catch performance of the silver-white jig was superior to that of the green jig in both winter (p<0.05) and autumn (P<0.001). Based on the catch performance results regarding the B-vessel in autumn, it is expected that the annual income increase that can be earned by using the silver-white jig will be KRW 26,385,000.

• Journal of the Optical Society of Korea
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• 제16권4호
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• pp.449-456
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• 2012

For two well-known modulation methods, stepwise current modulation (SCM) and pulse width modulation (PWM), the effects of driving current modulation conditions on chromaticity were experimentally investigated in a white LED lighting system. For the experimental implementation of both SCM and PWM, a white LED lighting was fabricated using phosphor converted (PC) white light emitting diodes (LEDs) and a driving circuit module was developed. By using them, the variations of illuminance, color coordinates, and spectrum were evaluated under various forward current conditions. Through the analysis in color coordinates, yellow shift in SCM and blue shift in PWM were observed on chromaticity diagrams with increasing average driving current. In addition, in order to analyze color deviation quantitatively, color distance before and after current increase, and the correlated color temperature (CCT) were calculated. As a result, for the white LED lighting in both modulation conditions, the maximum difference in the calculated CCT was obtained close to 1000 K. It means that careful consideration is required to be taken in the design of illumination systems to avoid serious problems such industrial accidents.

• 원예과학기술지
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• 제35권2호
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• pp.178-187
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• 2017

인공 광원에 따른 rocketsalad(Eruca sativa L.) 내 GSL 함량을 조사하였다. 실험에 사용한 광원의 종류는 자연광(Control-1 또는 2), Red LED, Blue LED, Mix(R+B) LED(Red LED+Blue LED), White LED, Fluorescent Lamp(FL), Fluorescent Lamp+UV-C(FL+UV-C). 실험은 식물 생장기 대수 제한 때문에 [실험 I;Control-1, Red LED, Blue LED, Mix(R+B) LED]과 [실험 II;Control-2, White LED, FL, FL+UV-C]로 구분하여 수행하였다. 그 결과, Red LED와 FL에서 rocket salad의 잎의 길이의 증가율이 가장 높았다. 그러므로 Red LED와 FL이 rocketsalad의 성장과 관계가 있음을 확인했다. Rocketsalad로부터 총 7종류의 GSLs(glucoraphanin, diglucothiobeinin, glucoerucin, glucobrassicin, dimeric 4-mercaptobutyl GSL, 4-methoxy glucobrassicin, gluconasturtiin)를 분리 및 동정하였다. [실험 I]에서 총 GSL 함량은 Red LED(4.30)에서 가장 높고 Blue LED($0.17{\mu}mol{\cdot}g^{-1}\;DW$)에서 가장 낮았다. [실험 II]에서 총 GSL 함량은 FL(13.45)에서 가장 높고 FL+UV-C($0.39{\mu}mol{\cdot}g^{-1}\;DW$)에서 가장 낮았다. 특히 Rocket salad의 강한 향과 매운 맛을 돋아주는 dimeric 4-mercaptobutyl 함량은 [실험 II]에서 Control-2에 비해 FL과 White LED가 각각 14.9, 3.2배 증가했다. 따라서 Red LED, White LED, FL은 rocket salad의 GSL 축적에 영향을 주었다고 판단된다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1956-1957
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• 2011

본 연구는 White LED를 이용하여 주변 밝기 변화에 빠르게 적응하는 퍼지 뉴로 Dimming Control System을 설계한다. 본 논문에서는 방사형기저함수 신경회로망(Radial Basis Function Neural Network: RBFNN)을 설계하여 실제 White LED Dimming Control System에 적용시켜 모델의 근사화 및 일반화 성능을 평가한다. 제안한 모델에서의 은닉층은 방사형기저함수를 사용하여 적합도를 구현하였고, 후반부의 연결가중치는 경사하강법을 사용한다. 이때 멤버쉽 함수의 중심점은 HCM 클러스터링 (Hard C-Means Clustering)을 적용하여 결정한다. 연결가중치는 4가지 형태의 다항식을 대입하여 출력을 평가하였다. 최종 출력의 최적화를 위하여 PSO(Particle Swarm Optimization)을 이용하여 은닉층 노드수 및 다항식 형태를 결정한다. 본 논문에서 제안한 LED Dimming Control System은 Atmega8535를 사용하여 PWM 제어 방식을 사용하고, 조도계(Cds)를 이용하여 LED의 밝기에 따른 주변의 밝기를 감지하여 조명에 적응시키는 방법을 적용하였다.

• 한국수산과학회지
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• 제39권6호
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• pp.480-486
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• 2006

The radiation characteristics of a high-luminance light-emitting diode (LED) light source were studied to evaluate its potential as an energy-saving light source for fishing lamps. The angle of the LED light source with 50% illuminance was $8-15^{\circ}$, and it had strong directional characteristics. The wavelengths at which the radiance and irradiance were maxima were 709, 613, 473, 501, 525, and 465 nm for red, orange, blue, peacock blue, green, and white light, respectively. The underwater transmission characteristics of the LED light source were superior in the order blue, white, peacock blue, and green in optical water type I: blue, peacock blue, white, and green in optical water type II; and blue, peacock blue, green, and white in optical water type III. Setting the underwater transmission characteristics of the LED light source in optical water type I at 100%, the transmission of water types II and III decreased to 67 and 17%, respectively. Based on the underwater transmission characteristics calculated in optical water types I-III, the blue and peacock blue LED light sources can be used as an energy-saving light source for fishing lamps.

• Bulletin of the Korean Chemical Society
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• 제28권8호
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• pp.1280-1284
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• 2007

A series of Ca1-xSrxS:Eu (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) phosphors were synthesized by solid-state reactions. The Ca1-xSrxS:Eu phosphors have a strong absorption at 455 nm, which corresponds to the emission wavelength of a blue LED. The emission peak of Ca1-xSrxS:Eu is blue shifted from 655 to 618 nm with increasing Sr content. The characteristics of Ca1-xSrxS:Eu phosphors make them suitable for use as wavelengthtunable red-emitting phosphors for three-band white LEDs pumped by a blue LED. In support of this, we fabricated a three-band white LED by coating SrGa2S4:Eu and Ca0.6Sr0.4S:Eu phosphors onto a blue LED chip, and characterized its optical properties.

• 반도체디스플레이기술학회지
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• 제16권4호
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• pp.11-15
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• 2017

Red phosphors, $Sr_2Si_5N_8:Eu^{2+}$, were synthesized as a single-phase crystal structure by optimizing carbon and $Eu^{2+}$ contents in a carbothermal reduction nitridation method. With increasing $Eu^{2+}$ contents, the photoluminescence spectra were red-shifted from 600 nm peak for 1 mol% for to 700 nm for 7 mol%. It was suggested that this red shift is attributed to the energy transfer from one low-energy sited $Eu^{2+}$ (1) to other high-energy sited $Eu^{2+}$ (2). Finally, the best red sample (620 nm emission peak and 80 nm half width for 3 mole% of $Eu^{2+}$) was packaged on a Blue LED together with two additional green and yellow phosphors, the fabricated White LED showed a high color-rendering index of 90 and white color coordinates of x= 0.321 and y = 0.305.

• 산업경영시스템학회지
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• 제46권3호
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• pp.59-68
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• 2023

Currently, yellow phosphor of Y3Al5O12:Ce3+ (YAG:Ce) fluorescent material is applied to a 450~480nm blue LED light source to implement a white LED device and it has a simple structure, can obtain sufficient luminance, and is economical. However, in this method, in terms of spectrum analysis, it is difficult to mass-produce white LEDs having the same color coordinates due to color separation cause by the wide wavelength gap between blue and yellow band. There is a disadvantage that it is difficult to control optical properties such as color stability and color rendering. In addition, this method does not emit purple light in the range of 380 to 420nm, so it is white without purple color that can not implement the spectrum of the entire visible light spectrum as like sunlight. Because of this, it is difficult to implement a color rendering index(CRI) of 90 or higher, and natural light characteristics such as sunlight can not be expected. For this, need for a method of implementing sunlight with one LED by using a method of combining phosphors with one light source, rather than a method of combining red, blue, and yellow LEDs. Using this method, the characteristics of an artificial sunlight LED device with a spectrum similar to that of sunlight were demonstrated by implementing LED devices of various color temperatures with high color rendering by injecting phosphors into a 405nm deep blue LED light source. In order to find the spectrum closest to sunlight, different combinations of phosphors were repeatedly fabricated and tested. In addition, reliability and mass productivity were verified through temperature and humidity tests and ink penetration tests.

• Journal of Advanced Marine Engineering and Technology
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• 제39권4호
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• pp.495-500
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• 2015

우리나라 주요 양식어종은 넙치, 조피볼락, 참돔이 전체 양식어종의 80% 이상을 차지하고 있다. 본 연구에서는 양식 어종의 다양화와 그에 따른 새로운 양식기법 도입을 위하여 LED파장을 이용하여 강도다리의 성장률을 계측하여 성장에 최적한 LED 파장을 규명하였다. 본 연구에 사용된 LED 파장의 조건은 Red 645nm, Green 525nm, Blue 465nm, 3차 혼합색인 White LED를 사용하였고, 전압의 차이에 따라 각 파장별 Package 배열에 차이를 두었다. 또한 연구에 사용된 조명은 적분구 측정을 통해 동일한 양의 방사속을 조사하도록 조절하여 진행하였으며 실험에 사용된 자어의 평균 체중은 $17.1{\pm}3.3g$, 체장은 $101.5{\pm}12.6mm$이였다. 자어는 사각형($60{\times}45{\times}45cm$) 순환 여과식 수조에 각각 10미씩 수용하여 12주간 사육하였고 매 1주에 체중 및 체장을 계측하여 성장률을 조사하였다. 연구 결과 Green 실험구에서 가장 높은 체중 증가율이 54.03%로 가장 높았으며 다음으로 White 실험구에서 38.47%, Red 실험구에서 36.98% Blue 실험구에서 34.72%로 나타났으며, 체장의 증가도 또한 Green 실험구에서 14.36% 가장 높았으며, White, Red, Blue 순서로 체장의 증가율이 나타났다. 본 연구결과로 강도다리는 사육환경에서 조명에 대한 영향을 크게 받는 것을 알 수 있으며, 나아가서 양식현장에의 적용 가능한 양식용 특수조명 개발과 공학을 기반으로 한 새로운 수산-LED 융합기술의 발전방향을 선도하는 중요한 기초연구가 될 것으로 판단된다.