• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.3
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• pp.285-291
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• 2010

In this paper, we demonstrate that indoor wireless optical communication is possible with an LED and a solar cell. A lighting LED is used for lighting and signal transmission. A solar cell is used for collecting light energy and signal detection. This scheme is very useful because transmission is possible without any additional communication systems. In experiments, wireless optical communication was carried out at a data rate of 9.6 kbps using a lighting LED and a solar cell.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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• pp.557-560
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• 2008

The main goal of this work is to fabricate light emitting diode (LED) module and apply it to mobile handset. We first fabricated the blue-color LED based on the AlInGaN cell structure with size of $200\;{\mu}m\;{\times}\;200\;{\mu}m$. Also we proposed a new $1.0\;mm\;{\times}\;0.5\;mm$ (1005size) packaging procedure for the LED cell. Thus the overall dimension of our LED cell was as small as $1.0\;mm\;{\times}\;0.5\;mm\;{\times}\;0.4\;mm$ ($W\;{\times}\;L\;{\times}\;T$). As far as we knew it was the first time that this small LED cell dimension had been fabricated and operated.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.70-77
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• 2020

Microalgae are independent organisms that perform photosynthesis and can alter the culture environment to increase accumulation of useful substances derived from microalgae. In this study, cell growth was measured by incubation for 39 days using MBBM, Neo medium, and seven light sources, which is the main factor affecting cell growth of microalgae S. obliquus. In the case of S. oliquus, which grew in MBBM and Neo medium, cell growth was highest under fluorescent light sources and Red2 LED (R660) light sources, and cell growth was lowest under Infra Red LED (R741) light sources. The average cell growth rate was 17.7% for MBBM and 15.4% for Neo. Comparing the effects of dry cell weight of Neo medium containing nutrients on the production of aquatic plants, MBBM and dry cell weight of Neo resulted in higher cell growth than Neo medium under all LED light sources except for Blue LED (B450). This proves that MBBM is more suitable for increasing the cell growth of microalgae than Neo medium and confirms that light source selection is important in the production of useful materials through mass cultivation of microalgae in the future.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.1
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• pp.1-10
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• 2007

To verify the inhibitory or protective effects of light-emitting diode(LED) irradiation on apoptotic cell death induced by $CoCl_2$, human SH-SY5Y cells were treated with $CoCl_2$ and LED were used to irradiate the cells. In the cell viability assay, cells were died slowly from $50{\mu}M$ to $250{\mu}M$ and about 50% of cells died after 12 hours at $400{\mu}M$ of $CoCl_2$. The Diff-Quik staining revealed that cells showed condensation of DNA and blebbing of the cell membrane. The DNA fragmentation assay revealed the DNA fragmentation, which is another apoptosis marker, occurred in cells treated with $400{\mu}M$ $CoCl_2$ for 16 hours. In the western blot for HIF-$1{\alpha}$, HIF-$1{\alpha}$ was expressed after 3 hours from induction and peaked maximally at 16 hours. In the cell viability assay of the effects of LED irradiation (at 590 nm for 1 hour 20 minutes), the cells showed more proliferation (about 20%) than the control group. The RPA assay of various apoptosis-related molecules showed that pro-apoptosis molecules such as Bax, Bak, and Bid were upregulated in the $CoCl_2$ treatment group. This means that the apoptotic cell population was increased. However there was some significant changes in LED irradiated cells. In the $CoCl_2$-treated LED irradiation group, those molecules were down-regulated more than in the only $CoCl_2$-treated group. These results have shown that $CoCl_2$ may induce apoptotic cell death in human SH-SY5Y neuroblastoma cells. And LED irradiation has a positive effect on apoptotic cells by down-regulation of pro-apoptotic molecules.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.512-513
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• 2008

The study examined what effects 100kHz PWM LED light irradiation causes to bone marrow cells of SD-Rat when LED characterized cheap and safe is used onto the light therapy by replacing the low 1evel laser. We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Consequent1y, the current value could be controlled by the change of 1eve1 in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage. MTT assay method was chosen to verify the cell increase of two groups and the effect of irradiation on cell proliferation was examined by measuring 590nm transmittance of ELISA reader. As a result, the cell increase of Rat bone marrow cells was verified in 100kHz PWM LED light irradiation group as compared to non-irradiation group.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2008.05a
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• pp.107-112
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• 2008

Solar Cell을 이용한 15W 휴대용 조명 시스템을 개발하기 위하여, 휴대용에 적합한 solar cell을 선정하고, Solar Cell을 충전하기 위한 태양광 궤적 변화에 대한 Simulation을 행하였으며, 1W 백색 LED 6EA를 사용하여 휴대용 LED Lighting System을 개발하였다. LED Lighting System은 solar cell 충방전 회로 및 LED SMPS 구동회로 설계, 글레어차단을 위한 리플렉터 설계, 방열 설계 및 기구 구조 설계를 통하여 개발되었으며, 직접 시제품을 제작하고 그 성능을 측정하였다.

• New & Renewable Energy
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• v.5 no.4
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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).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.19 no.12
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• pp.1149-1153
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• 2006

We developed the equipment palpating cell proliferation using a high brightness LED. This equipment was fabricated using a micro-controller and a high brightness LED, and designed to enable us to control light irradiation time, intensity, frequency and so on. Especially, to control the light irradiation frequency, FPGA was used, and to control the change of output value, TLC5941 was used. Control stage is divided into 30 levels by program. Consequently, the current value could be controlled by the change of level in Continue Wave(CW) and Pulse Width Modulation(PWM), and the output of a high brightness LED could be controlled stage by stage.

• Korean Journal of Clinical Laboratory Science
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• v.49 no.2
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• pp.150-160
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• 2017

Atopic dermatitis (AD) is a chronic inflammatory skin disease. It is characterized by eczematous lesions, skin dryness, and pruritus. The existing treatment drugs for AD have side effects, especially if the drugs are taken for extended periods. Therefore, new alternative therapies are necessary. The aim of this study was to investigate the combined effects of curcumin administration and LED irradiation on AD. AD-like lesions were induced in BALB/c mice by repeated application of 1-chloro-2,4-dinitrobenzene (DNCB) to the shaved skin of the ear and neck. Thirty male BALB/c mice were divided into five groups: vehicle, DNCB, curcumin, LED, and curcumin+LED groups. Curcumin (0.1 g/kg/day) was administrated repeatedly during a period of 14 days (experimental period) and 630 nm LED irradiation ($5J/cm^2/day$) was performed in the acryl box once a day for 10 days, after inducing AD-like lesions via DNCB application. The severity of AD-like lesions was evaluated during the experimental period, using a modified SCORAD index. Both ear and neck skin tissues were examined histologically for epidermal thickness, mast cell, eosinophil counting, and dermal collagen density. Epidermal cell proliferation and apoptosis were detected using immunohistochemistry and TUNEL, respectively. These were all reduced in SCORAD index, epidermal thickness, collagen density, number of mast cell and eosinophil in dermis, and number of proliferating cell and apoptotic cell in epidermis by curcumin administration and 630 nm LED irradiation. Moreover, all parameters were significantly lower in the curcumin+LED group compared with the curcumin group and LED group. These results suggest that the combined therapy of curcumin and LED is more effective than a single treatment. We recommend that this can be a feasible alternative therapy to manage AD.

• Journal of Sensor Science and Technology
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• v.24 no.4
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• pp.232-238
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• 2015

In this paper, we introduce a passive transponder in which an LED is used for both a light transmitter and a receiver, and a solar cell is used for supplying power to the all devices in the transponder. The LED in the transponder operates as a photodetector in the receiving mode, and acts as a light source in the transmitting mode. The current responsivity of the LED detector was measured to be in the order of $10^{-4}A/W$, and the receiving bandwidth with a load resistance of $10k{\Omega}$ was about 10 to 30 kHz. Using the LED for an optical transceiver in a VLID transponder, the detection range was about 70 cm when the transponder was illuminated by the visible light from a $3{\times}3$ LED array in a reader.