• 조명전기설비학회논문지
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• 제18권2호
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• pp.8-15
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• 2004

본 논문은 RGB LED를 이용한 백색 전구의 색혼합 향상에 관한 것이다. RGB LED를 이용하여 전구를 설계하였을 경우, LED의 위치에 따라 광선의 진행 경로가 틀려 색혼합이 잘 되는 않는다. 따라서 각각의 LED에 경사렌즈를 씌워서 광선의 진행경로를 전구의 중심축으로 향하게 하여 주었다. 색혼합 정도는 MacAdam ellipse 이론을 이용하여 평가하였다.

• 한국전자통신학회논문지
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• 제16권2호
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• pp.219-226
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• 2021

LED-to-LED VLC(: Visible Light Communications) 기술은 기존의 VLC 기술과 달리 송신부와 수신부를 모두 LED로 사용한 기술이다. 본 논문에서는 Micro LED를 송신부로 사용한 Micro LED-to-LED VLC 기술을 연구하였다. Red, Yellow, Green, Blue, White 색상의 송/수신부 LED에 따라 통신 시스템의 상승 시간과 신호 대 잡음비를 측정하여 채널 용량을 비교하였다. 본 실험 결과에 따르면, 송신부 Micro LED가 Blue이고 수신부 LED가 Green일 때에 통신 시스템 중에서 가장 좋은 결과인 125 kbps의 채널 용량을 갖는 것을 확인하였다. 또한, OFDM(: Orthogonal Frequency Division Multiplexing) 신호를 사용하여 비트 에러율을 확인한 결과, 250 kbps까지는 통신이 가능함을 실험적으로 확인하였다.

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.87-95
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• 2014

Purpose: The purpose of this study was to design a variable frequency LED light system for plant factory which combined red, blue, green, white, and UV lights and controlled the ratio of the light wavelength. In addition, this study evaluated the performance of each combination of LED to verify the applicability. Methods: Four combinations of LED (i.e. Red+Blue, Red+Blue+Green, Red+Blue+White, Red+Blue+UV) were designed using five types of LED. The system was designed to control the duty ratio of each wavelength of LED by 1% interval from 0~100%, the pulse by 1Hz interval from 1~20kHz. Response characteristics of the control system, spectral distribution of each combination, light uniformity and uniformity ratio were measured to test the performance of the system. Results: Clean waveforms were measured from 10Hz to 10kHz regardless of duty ratio. Frequency distortion was observed within 5% of inflection point at frequencies above 10kHz regardless of duty ratio, but it was judged negligible. Spectra showed a normal distribution, and maximum PPF with duty ratio of 100% was $271.4{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ for the Red+Blue combination. PPF of the Red+Blue+Green combination was $258.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, and that of the Red+Blue+White combination was $273.9{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. PPF of the Red+Blue+UV combination was $267.7{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$. Uniformity ratio for the area excepting border showed 0.90 for the Red+Blue and Red+Blue+White combinations, 0.87 for the Red+Blue+Green combination, and 0.88 for the Red+Blue+UV combination. The light was irradiated evenly at the area excepting border, so it was suitable for plant growing. Conclusions: From the results of this study, response characteristics of the control system, spectral distribution of each combination, light uniformity and uniformity ratio were suitable for applying into the plant factory.

• 한국환경과학회지
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• 제22권11호
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• pp.1499-1508
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• 2013

In the results of investigating the role of LED light quality in enhancing the ornamental value of indoor foliage plants, amber and red light increased plant height, leaf width, and leaf stalk, and the consequent tree shape decreased the ornamental value. The chlorophyll content increased significantly under white light and compound light. With regard to the effect of plant leaf color on ornamental value, the value of lightness was markedly enhanced by red light. As to the functionality of plants according to photosynthetic activity, plants such as Dieffenbachia, Clusia, and Dracaena were found favorable to those staying indoors for a longtime from morning to evening. Spathiphyllum, and Ficus were found to be recommendable for indoor spaces used actively during afternoon because their photosynthesis was activated in the afternoon. With regard to power consumption according to light quality, white light consumed 119 W/hour, around 45% lower than that of fluorescent lamps, so it is considered the optimal artificial light quality that can enhance energy efficiency. Red light consumed 72 W/hour, only 33% of that of fluorescent lamps, but it was not considered the optimal light quality because plant growth was poor under the light quality. White light and compound light were found to be the ideal light sources for improving the functionality and ornamental value of indoor plants and reducing the cost of maintenance, but because compound light hinders people from recognizing the original color of plants and makes their eyes easily tired, white light was considered the optimal light satisfying all of the ornamental value, economic efficiency and functionality resulting from plant growth.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.II
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• pp.1507-1509
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• 2005

LCD(Liquid Crystal Display) products is needed to have high reliability and are produced without harmful material. Because Substitution for CCFL of Light source used to Conventional backlight unit, research is going about product with LED of light source at present. In this experiment, We made the LED backlight unit with high quality for automotivenavigation. This backlight unit has center luminance of 6500 nit at15W power consumption. We adjusted chromaticity by using ten Blue LED and eight side emitting type White LEDs with high power LED from Lumileds company.

• 현장농수산연구지
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• 제22권2호
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• pp.123-133
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• 2020

시설 재배지 내 담배가루이의 밀도 예찰을 위하여 여러 종류의 LED등(청색등, 녹색등, 적색등, 백색등)에 대한 유인력을 평가하였다. 유인력 평가는 황색끈끈이트랩에 부착된 담배가루이의 포집 수를 대상으로 하였다. 평가용 케이지 내에서 기주식물이 없는 조건에서 유인력은 청색등(107.3±2.5마리) > 백색등(83.0±12.1마리) > 적색등(58±21.8마리) > 녹색등(39.7±8.1마리) 순서로 나타났다. 먹이를 주입한 상태에서 유인력은 청색등(52±17.4) > 적색등(38.7±5.8) > 녹색등(12.7±1.5) > 백색등(11.7±5.0) 순서로 관찰되었다. 두 실험 조건에서 모두 청색등에서 유인력이 가장 높은 것으로 나타났다. 기주식물을 넣었을 때 LED등 유인력이 감소하는 것을 확인하였는데, 백색등(85.9%) > 녹색등(68.1%) > 청색등(51.6%) > 적색등(33.3%) 순서로 나타나 기주식물이 LED 등 유인력 감소에 영향이 있음을 확인하였다. 상대적인 방제력 평가에서는 기주식물을 처리한 6시간 이후에 적색등(66.7%) > 청색등(48.5%) > 녹색등(31.9%) > 백색등(14.1%) 순으로 높았다(F_3,8 = 14.7, P = 0.001). 따라서 청색등은 초기 유인력이 매우 높은 특징을 보였고, 적색등은 기주식물의 투입에 영향을 받지 않아 담배가루이 유인에 적합성이 있음을 확인하였다. 야외 실증실험에서는 낮은 온도조건에 의해 높은 유인력은 관찰되지 않았지만, 청색등과 적색등에서 대조구 대비 높은 유인력이 관찰되었다. 향후 적색과 청색을 활용한 LED등은 시설재배지 내 담배가루이의 예찰에 활용할 수 있을 것으로 기대된다.

• 반도체디스플레이기술학회지
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• 제17권4호
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• pp.37-41
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• 2018

$Y_3A_{l5}O_{12}:Ce^{3+},Pr^{3+}$ single crystal phosphor was prepared by floating zone method. single crystal was confirmed to have a Ia-3d (230) space group of cubic structure and showed regular morphology. The optical properties, single crystal exhibited a emission band from green, yellow wide wavelength and 610nm, 640nm red wavelength vicinity. The luminance maintenance rate was decreased by phonon with increasing temperature, but high luminance is maintained more than powder phosphor. In addition, $Y_3A_{l5}O_{12}:Ce^{3+},Pr^{3+}$ single crystal phosphor was applied to a high power blue laser diode, we implemented high power white laser lightings. and it was confirmed that thermal properties over time, due to the effective heat transfer of complete crystal structure. We confirmed that excellent radiant heat properties than powder phosphor was applied to a high power white laser diode.

• 한국ITS학회 논문지
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• 제8권2호
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• pp.83-90
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• 2009

백색 LED(Light Emitting Diode:발광다이오드)는 고휘도, 향상된 안정성, 낮은 전력 소비, 그리고 긴 수명 등 유리한 특성을 제공한다. LED는 전기 신호를 광신호로 변환시킴으로써 광통신 실내 무선 광 조명실뿐만 아니라, 무선 광 통신 시스템에도 사용되는 전자 소자이다. 현재 이러한 백색 LED에 대해서 다양한 연구가 진행 중이며, 본 논문에서는 이러한 백색 LED를 이용한 VLC(Visible Light Communication:가시광통신)의 다중 접속 방식을 논의한다. 제안된 시스템에서는 현 VLC 시스템의 간섭을 줄이고, 수용량을 늘리기 위해 CDMA(Code Division Multiple Access:코드 분할 다중 접속)를 VLC시스템에 적용한다. 또한 AWGN(Additive White Gaussian Noise) 채널과 Diffuse 채널에서의 OOK(On-off keying) 변조와 BPSK 변조를 사용한 VLC-CDMA통신 시스템을 비교해봄으로써 OOK 변조의 우수성을 결과의 분석을 통하여 나타내었다. 그리고 다중경로환경에서와 AWGN환경에서의 BER을 비교함으로써 다중경로에 의한 간섭의 해결의 중요성을 검토한다. 다중 접속 방식으로 인한 ISI(Inter Symbol Interference)를 제거하여 시스템의 효율을 높이기 위해 Directed LOS(Line Of Sight)와 Diffuse Link를 가정하여 광 확산 코드인 OOC(Optical Orthogonal Code: 광 직교 코드)를 적용한 VLC-CDMA를 제안하고, 성능 분석을 제시한다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1149-1152
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• 2008

Nitride semiconductor based light-emitting diodes attain a new functionality of polychromatic emission by the use of three-dimensionally faceted microstructures, which may lead to an advanced lighting technology in which the light source spectra are synthesized so as to meet requirements of the application.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1090-1092
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• 2006

There is provided white light illumination system including a radiation source, a first luminescent material having a peak emission wavelength of about 575 to about 620 nm, a second luminescent material having a peak emission wavelength of about 495 to about 550 nm, which is different from the first luminescent material and a third luminescent material having a peak emission wavelength of about 420 to about 480 nm, which is different from the first and second luminescent materials. The LED may be a UV LED and the luminescent materials may be a blend of three phosphors. A human observer perceives the combination of the blue, green and red phosphor emissions as white light.