• The Journal of Korean Institute of Communications and Information Sciences
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• v.36 no.7A
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• pp.635-639
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• 2011

As LED becomes more important in lighting system, LED-based communication draws much attention. Only a single color has been used for this purpose thus far. However, as emotional lighting becomes more important, the need for color visible light communication is growing. In this paper, a transmission scheme for RGB color based communication is proposed that can transmit data while changing color constantly.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1556-1557
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• 2007

LCD BLU에 광원의 수명을 측정하고, 고장모드를 분석하기 위해서는 광원을 구성하고 있는 각각의 성분 중에서 광원 자체를 구성하고 있는 R/G/B 광원에 대한 Burn-in test 및 고장모드를 분석하였다. LCD BLU에 있어서 R/G/B LED광원의 역할은 BLU 자체의 수명과 성능에 가장 큰 영향을 미친다. 서로 각각 사용조건하에서의 수명과 성능의 차이에 따라서 BLU 자체의 수명이 결정된다. 이를 평가가기 위해 LED device에 대한 가속수명테스트를 위한 Burn-in test를 실시하였으며, 발생한 고장모드를 분석하였다. 분석결과 누설전류 증가로 인한 불량이 주로 발생하였다. 누설전류 증가를 평가하기 위해 Photo emission microscope(PHEMOS-1000, MoDooTEK Inc.)을 이용하여 저전류에서의 LED chip의 누설전류에 의한 발광을 관찰함으로 인해, LED chip의 신뢰성 및 평가 기준이 됨을 알 수 있다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.3-6
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• 2009

This research is an experiment to examine on the realization of Natural Color using R, G, B LEDs and this experiment was performed to cover two different stages. 1) When Natural Color using R, G, B LEDs was realized without correction in first stage, all color(R, G, B, C, M, Y) series had highly range of error from 0.0200 to 0.1500. 2) When R, G, B of LEDs was mixed at the ratio of 1:4.5907:0.0601 for realization of white in second stage, white was not realized to excitation purity. The second stage was Performed based on the three primary colors theory found out by Thomas Young in England and Hermann Ludwig Ferdinand von Helmholtz in Germany.

• Food Science and Preservation
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• v.19 no.3
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• pp.354-360
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• 2012

The effect of the wavelength of the light emitted by the light-emitting diode (LED) on the growth characteristics and physicochemical and sensory qualities of Pleurotus eryngii were investigated. Pleurotus eryngii were grown under different light sources: blue light (450 nm), red light (650 nm), green light (525 nm), UV-A (365 nm), and mixed light ($B^*R$, $B^*G$, $R^*G$, $B^*R^*G^*UV-A$). The quantity of LED light was set up at 50% (LED: 64.9-108.0 $pmolm-2{\cdot}s-1$;fluorescentlight:11.7lux). Fluorescent light was used as control. There were no significant differences in the flesh firmness. In the case of the Pleurotuseryngii cultivated under red, green, and mixed light ($R^*G$), the color of the pileus and the length of the stipe were similar to those of the control group. The sensory scores were not significantly different between the LED lights (red, green, and $R^*G$) and the control. Among the three LED light conditions, the sample cultivated under red light recorded the highest score. The samples under UV-A, blue, and mixed light ($B^*R$, $B^*G$, $B^*R^*G^*U$) had a dark pileus color and had a short stipe. These results showed that the wavelength of LED light affected the growth and quality characteristics of Pleurotus eryngii, and that using red LED light is preferable for the cultivation of Pleurotus eryngii with better quality.

• Journal of Plant Biotechnology
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• v.35 no.3
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• pp.215-221
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• 2008

Effects of light generated by LEDs on shoot growth and rooting of Tsuru-rindo(Tripterospermum japonicum) were evaluated. Apical shoots(one or two node with 3-4 leaves) were cultured on MS basal medium with 3% sucrose and maintained for four weeks under five different light qualities: fluorescent lamp(F), 100% red LED(R), 70% red LED+30% blue LED(R7B3), 50% red LED+50% blue(R5B5), or 100% blue LED(B). Rooting was promoted by both red light and fluorescent lamp, and the effect was further promoted under the ventilation. Red light enhanced shoot node elongation, whereas blue light appeared to suppress it. Growth of shoots and leaves were enhanced under the ventilation irrespective of the different light qualities. Under the ventilated condition, total fresh weight of plants was highest in R7B3 LED as 257.7 mg per plant. Dry matters, which are used for index of plant growth, were lowest under red light, whereas it was highest under blue light. The dry matter was inclined to getting higher by ascending the ratio of blue light and red light. Total chlorophyll content was highest in both R7B3 LED and R5B5 LED under ventilation as 29.5 and 31.2, respectively. Above results suggest that light quality optimization could be an important factor to foster in vitro growth of the species. Ventilation treatment appeared to be another important factor to induce normal shoot growth and rooting.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.141-144
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• 2009

LED Lightings market remains highly fragmented, encompassing many niche applications. Architectural lighting is the largest and many applications are for colored (R, G, B) light. Hundreds of companies worldwide are participating at the luminaire or fixture level. Standard setting is on a fast track. The larger LED lightings market scale, the more important standardization of performance evaluation techniques to clearly prescribe the product specification.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2159-2161
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• 2000

The LEDs are used for signal lights including traffic signals and telecommunication equipments. Advanced foreign countries are making R&D of ultra high intensity LEDs, and the LEDs are expected to new light source. Optical characteristics by measurements of 14 LEDs; each 2 of 3$\Phi$ R/G/Y LEDs, each of 5$\Phi$ Y/G/Y LEDs and each of high intensity 5$\Phi$ R/G/B/A/W LEDs. Comparison on chromaticity coordinate of high intensity 5$\Phi$ White LED by forward V/I.

• Journal of Bio-Environment Control
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• v.27 no.4
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• pp.371-380
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• 2018

Aim of this study was to investigate the effects of different nutrient solutions and various light qualities generated by LED on the growth and glucosinolates contents of watercress (Nasturtium officinale) grown under hydroponics for 3 weeks. The seeds of watercress were sown on crushed rockwool media and raised them for two weeks. They were transplanted in a semi-DFT (deep flow technique) hydroponics system. A controlled-environment room was maintained at $20{\pm}1^{\circ}C$ and $16{\pm}1^{\circ}C$ temperatures and $65{\pm}10%$ and $75{\pm}10%$ relative humidity (day and night, respectively), with a provided photosynthetic photon flux density (PPFD) of $180{\pm}10{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ and a photoperiod of 16/8h. To find out the best kinds of nutrient solutions for growing watercress, Otsuka House 1A (OTS), Horticultural Experiment Station in Korea (HES), and Netherland's Proefstaion voor Bloemisterij en Gasgroente (PBG) were adapted with initial EC of $1.0-1.3dS{\cdot}m^{-1}$ and pH of 6.2, irradiating PPFD with fluorescent lamps (Ex-1). Either monochromatic (W10 and R10) or mixed LEDs (R5B1, R3B1, R2B1G1, and W2B1G1) were irradiated with a differing ratio of each LED's PPFD to understanding light quality on the growth and glucosinolates contents of watercress (Ex-2). Although significant difference in the shoot growth of watercress was not found among three nutrient solutions treatments, but the root fresh weight increased by 13.7% and 55.1% in PBG and OTS compared to HES, respectively. OTS increased the gluconasturtiin content by 96% and 65% compared to PBG and HES. Compared with the white light (W10), the red light (R10) showed a 101.3% increase in the shoot length of watercress. Increasing blue light portion positively affected plant growth. The content of total glucosinolates in watercress was increased by 144.5% and 70% per unit dry weight in R3B1 treatment compared with R2B1G1 and W10 treatments, respectively. The growth and total glucosinolates contents of the watercress were highest under R3B1 among six light qualities.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.93-96
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• 2008

Recently, as development of the luminaire industry, many people are interest of the outdoor and indoor lighting environment. Also, as increasing of people activity at night, the role of lighting is more important. In these days, the issue of LEDs lighting environment is using loud colors of LEDs which are the most of primary colors (R, G, B). It is often disliked by same people. Therefore, it is necessary to use of natural color in lighting design using LEDs. The colors of the LEDs are composed of combination of R, G, B diodes. This paper performs to investigate preference of various colors and color patterns of LEDs. The purposes of this study are to suggest standardization and natural colors instead of primary colors using LEDs.

• Horticultural Science & Technology
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• v.35 no.2
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• pp.178-187
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• 2017

The aim of this study was to investigate the effect of different light sources on the levels of glucosinolates (GSLs) in rocket salad (Eruca sativa L.). The light sources used in the study were: natural light (Control-1 or 2), red light-emitting diodes(LEDs), blue LEDs, mixed red and blue LEDs (R+B LEDs), white LEDs, fluorescent lamps (FL), and fluorescent lamps plus UV-C (FL+UV-C). Two separate experiments were conducted [Experiment I: Control-1, Red LED, Blue LED, Mix (R+B) LED and Experiment II: Control-2, White LED, FL, FL+UV-C] because of the limited number of growth chambers in our laboratory. The rate of increase in the length of rocket salad leaves was the highest under red LEDs and, FL confirming that red LED and, FL affect the growth of rocket salad. We separated and identified seven types of GSLs from the rocket salad:glucoraphanin, diglucothiobeinin, glucoerucin, glucobrassicin, dimeric 4-mercaptobutyl GSL, 4-methoxyglucobrassicin, and gluconasturtiin. The highest total GSL contents in Eexperiment I was found in plants grown under in red LEDs ($4.30{\mu}mol{\cdot}g^{-1}\;dry$ weight, DW), and the lowest under blue LEDs ($0.17{\mu}mol{\cdot}g^{-1}\;DW$). The highest total GSL contents in Experiment II was found in plants grown under FL ($13.45{\mu}mol{\cdot}g^{-1}\;DW$), and the lowest in FL+UV-C ($0.39{\mu}mol{\cdot}g^{-1}\;DW$). Especially in Experiment II, the content of dimeric 4-mercaptobutyl, which has a strong aroma and spicy flavor in rocket salad, was higher under FL and white LEDs than in Control-2, increasing by approximately 14.9 and 3.2-fold respectively. Therefore, light sources such as red LEDs, white LEDs and FL affected the accumulation of GSLs in rocket salad.