• Transactions on Electrical and Electronic Materials
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• 제12권6호
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• pp.253-257
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• 2011

This study was carried out to solve problems such as radio frequency band depletion, confusion risk, and security loss in existing visible wireless communication systems, and to determine the applicability of next-generation networks. A light-emitting diode (LED) light communication system was implemented with a controlling switching light module using the ATmega16 micro-controller. To solve the existing modulation effect and disturbance in visible light communication, an integrated interface was evaluated with a driving light module and analyzes its reception property. A transmitter/receiver using the ATmel's micro-controller, high-intensity white LED-6 modules, and infrared sensor KSM60WLM and visible sensor TSL250RD were designed. An experiment from the initial value of distance to 2.5 m showed 0.46 V of the voltage loss, and if in long distance, external light interference occurred and light intensity was lost by external impact and thus data had to be modified or reset repeatedly. Additionally, when we used 6 modules through the remote controller's lighting dimming, data could be transmitted up to 1.76 m without any errors during the day and up to 2.29 m at night with around 2~3% communication error. If a special optical filter can reduce as much external light as possible in the integrated interface, the LED for lighting communication systems may be applied in next generation networks.

• 한국ITS학회:학술대회논문집
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• 한국ITS학회 2010년도 춘계학술대회
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• pp.141-144
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• 2010

• Journal of Ginseng Research
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• 제36권2호
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• pp.198-204
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• 2012

An light-emitting diode (LED)-based light source was used as a monochromatic light source to determine the responses of raw ginseng roots (Panax ginseng Meyer) to specific emission spectra with respect to the production of ginsenosides. The ginsenoside content in the ginseng roots changed in response to the LED light treatments at $25^{\circ}C$ relative to the levels in the control roots that were treated in the dark or at $4^{\circ}C$ for 7 d. Ginseng roots were exposed to LEDs with four different peak emission wavelengths, 380, 450, 470, and 660 nm, in closed compartments. Compared with the control $4^{\circ}C$-treated roots, roots that were treated with 450 and 470 nm light showed a significantly increased production of ginsenosides (p<0.05), with increases of 64.9% and 74.1%, respectively. The contents of the ginsenosides $Rb_2$, Rc, and $Rg_1$ were significantly higher (p<0.05) in the 450 and 470 nm-treated root samples. The ratio of protopanaxadiol ginsenosides ($Rb_1$, $Rb_2$, Rc, and Rd) to protopanaxatriol ginsenosides ($Rb_1$, $Rb_2$, Re, and Rf) was significantly higher (p<0.05) in the 450 and 470 nm-treated root samples than in the control $4^{\circ}C$-treated roots. This is the first report that demonstrates the increase and conversion of ginsenosides in raw ginseng roots in response to exposure to LED light.

• 센서학회지
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• 제31권1호
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• pp.31-35
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• 2022

The efficacy improvement of the light emitting diode (LED) was studied for the realization of small-size, low power consumption, and highly sensitive bio-sensor instrument. The performance of the LED with Mg delta-doping at the interface of AlGaN/GaN super-lattice in p type cladding layer was simulated. The device with Mg delta-doping showed improved current, radiative recombination rate, electroluminescence, and light output power compared to the conventional LED structure. Under the bias condition of 5 V, the improved device exhibited 20.8% increase in the light output power. This is attributed to the increment of hole concentration from stable ionization of Mg in p type cladding layer. This result is expected to be used for the miniaturization, power saving, and sensitivity improvement of the bio-sensor system.

• 한국수산과학회지
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• 제50권4호
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• pp.413-420
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• 2017

The increase in the number of mud shrimps Upogebia major is a concern because of their negative effects on shellfish aquaculture, including Manila clam Venerupis philippinatum along the west coast of Korea. This study developed a behavioral analysis system for aquatic animals using a set of monochromatic light-emitting diode (LED) modules covering the visible light range at similar intervals. Movements of mud shrimp were monitored using a tracking system under illumination with infra-red light and an LED of 660 nm wavelength without provoking stimulation. The minimum light intensity needed to induce a photoresponse by the mud shrimp was $10{\mu}mole/m^2/s$ under the conditions tested. Of the six kinds of LED illuminations tested, the most sensitive response was obtained with illumination with the 505 nm LED, followed in order by LEDs with peak wavelengths of $525nm{\fallingdotseq}465nm$ > $405nm{\fallingdotseq}590nm$ > 660 nm. These findings should help to identify LED sources that efficiently induce movement of the mud shrimp and also for monitoring movement without stimulating.

• 한국정보통신학회논문지
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• 제16권11호
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• pp.2431-2436
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• 2012

본 논문에서는 LED(Light Emitting Diode)조명을 통해 통신을 접목하여 이용이 간편한 가시광통신 시스템을 구현 하고자 한다. LED 가시광 통신을 실현시키고자 송신부에는 1~12개의 LED 발광 소자와 수신부에는 가변 PD(Photo Diode)인 센서를 사용한다. LED가시광통신을 하고자 개발이 이루어진 송 수신부의 초기 거리 값은 0~1.5m 이상으로 하고, 전체 시스템 전송 속도는 수 천 kbps의 가변성을 가지는 가시광 미디어 전송 시스템을 이루었다. LED 모듈의 전체적인 효율 증대를 위해 렌즈 착용시와 미착용시 성능 실험을 하여 효율 측정을 하였으며, 구현된 연구의 성능 분석을 위한 기존 PC 모듈에 LED 및 PD를 구성하여 LED 개수, 전송속도에 따른 최대 송수신의 통신 거리를 실험하고 응용 방법과 가능성에 대해서 확인하고자 한다.

• 한국전기전자재료학회논문지
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• 제28권5호
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• pp.277-284
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• 2015

The humans are under attack involving the hazardous environment and pathogen/biotoxin aerosol that is realistic concerned. A portable, fast, reliable, and cheap Pathogen and Biotoxin Aerosol threat Detection(PBAD) trigger is an important technology for detect-to-protect and detect-to-treat system because the man-made biological terror is a fast and lethal infection. The ultraviolet C(UVC) wavelengths light source is key issue for PBAD that is sensitive because of strong fluorescence cross section from fluorescent amino acids in proteins such as tryptophan and tyrosine. The UVC-light emitting diode(LED) is emerging light source technology as alternative to laser or lamps as they offer several advantages. This paper discussed about the design consideration of UVC-LED for the PBAD system. The UVC-LED and PBAD technology, currently available or in development, are also discussed.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 춘계학술대회 논문집
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• pp.205-208
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• 2008

본 논문에서는 LED(light emitting diode)조명과 CNT(carbon nano-tube)조명에 대한 전기적인 특성과 광학적 특성을 측정하여 비교하고 고찰하였다. 특히 IES format 파일을 사용하여 각각의 조명등기구에 대한 LID(luminous intensity distribution) 분석과 조도 시뮬레이션을 수행하여 최대 및 최소, 그리고 평균조도 등을 분석하였다. 향후 LED 및 CNT 신광원은 면조명으로의 관련 기술기준 및 규격의 작성시 참고자료로 활용될 것으로 판단된다.

• 대한화학회지
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• 제48권4호
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• pp.371-378
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• 2004

기존의 $SrGa_2S_4:Eu^{2+}$ 녹색 발광 형광체는 주로 CRT (Cathode Ray Tube)용이나 FED (Field Emission Display), 그리고 EL (Electroluminescence)용 발광소자로 많이 연구되어졌다. 현재는 장파장 영역의 여기 특성을 이용한 LED (Light Emitting Diode)용 형광체로 주목 되어지고 있다. $SrGa_2S_4:Eu^{2+}$ 형광체의 일반적 합성 방법은 Flux를 이용하여 인체에 유해한 $H_2S$나 $CS_2$ 기체를 사용할 뿐만 아니라 높은 합성온도, 긴 반응시간 및 공정이 복잡한 단점을 지니고 있다. 따라서 본 실험은 황화물계 원료인 SrS, $Ga_2S_3$ 그리고 EuS를 출발 물질로 하여 $H_2S$ 기체를 사용하지 않고 혼합 기체$(5% H_2/95% N_2)$를 사용해 환원 분위기 하에서 $SrGa_2S_4:Eu^{2+}$을 합성하였다. 그리고 다양한 합성 조건과 LED용으로 사용되기 위해 수세처리와 Sieving 과정을 거친 형광체의 발광특성을 검토하였다.

• 조명전기설비학회논문지
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• 제25권6호
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• pp.9-17
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• 2011

The high-power LED (Light Emitting Diode) which is recently gaining popularity as a digital light source has such advantages as low power consumption, long life, fast switching speed, and high efficiency. Thus, many efforts are being made to use the high-power LEDs for general lighting. This paper proposes LED driving circuit uses a DC/DC converter that can recover energy to compensate for the current variations caused by changes in LED equivalent resistance following a temperature change instead of serial resistance. The maximum input voltage of this DC/DC converter has low voltage variations by temperature change when the rated current is formed. In order to return current to the input side, we need a high boosting at low power. Thus, to improve the low efficiency of power converter, the power converter can be configured in such a way to gather the powers of low-capacity DC/DC converters and return the total power. Experiments showed that the proposed system improved efficiency compared to the conventional LED drive using the existing DC/DC converter.