• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.11a
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• pp.416-417
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• 2008

This paper performed the basic study for developing the Photodynamic Therapy Equipment for medical treatment. We developed the 4channel light medical therapy apparatus for external injury cure using a LED light source. This equipment was fabricated by using microcontroller, and designed to enable us to control light irradiation timer, intensity and reservation. In this paper, the designed device was used to find out how 470nm LEDs light source affects the skin wound of RAT. In the experiment, $1cm_2$ wounds on the External injury of RAT were made. Light irradiation RAT and none light irradiation RAT divided, each RAT was irradiated one hour a day for 15 days. In result, compared with none light irradiation RAT, the lower incidence of inflammation and faster recovery was shown in light irradiation RAT.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2017.11a
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• pp.206-208
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• 2017

In recent years, we have been working on the improvement project of mercury 3-lecture type at the Geummundo lighthouse for more than 100 years. We have installed toxic mercury removal, LED light source, and dualization system for nonstop. It can be seen as an example. Circular restoration of the entire frame is performed, and the real-time status can be grasped through the installation of the double-ball bearing and the remote control system. After installation, optical measurement through Hanvit secured the optical performance of 2,000,000 cd of floating brightness of 300cd, proving the efficient possibility of introducing the domestic rotary type light source using LED light source.

• Journal of The Korea Institute of Healthcare Architecture
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• v.29 no.3
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• pp.29-36
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• 2023

Purpose: The purpose of this study is to find out whether the color change of the LED light source has a significant effect on the beta wave activity of EEG in the learning state. Methods: The subjects of the experiment were 20 male and female college students between the ages of 19 and 25 who routinely perform their studies. In the created learning environment, the EEG change according to the change in the lighting color was measured while solving the Mensa thinking ability problem while sitting on a desk with LED lights installed on the top and a chair with a footrest to stabilize the legs. The light source consisted of 3 ready-made colors and 6 newly created colors. A total of 9 color light stimuli were given for 2 minutes each, and the EEG change of the subject was observed. After the experiment, the correlation was analyzed based on the mid-beta wave data recorded on the QEEG according to the color change of light and the Mensa problem score. Results: It was found that the activation of mid-beta waves was stimulated in the temporal lobes (T5, T3, T6, T4) and occipital lobes (O1, O2) of all subjects who focused on solving Mensa thinking problems. As a result of comparing the top 20% and the bottom 20% of problem solving scores, the upper group had no effect of lighting, while the lower group showed increased beta wave activity in response to color light stimulation in the order of T4, T6, and T5. Implications: It was confirmed that the color of light that activates the middle beta wave varies greatly depending on the subject's attention and learning ability, and it is judged that the color of light including the green wavelength is helpful in activating the middle beta wave in the group with low learning ability.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.3
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• pp.1-6
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• 2004

Recently the examples of a designing a building-lighting to which LED, a solid state Lighting, is applied are increasing in number, but the development of lighting apparatus and the techniques applied to a designing lighting apparatus frequently don't fit to a new source of light. This essay refers to the matters relevant to the techniques for designing a lighting, which are controlled with a digital technology, and the effectiveness of a "Interactive-lighting technique" which has a ductility by a sensor with developing a digital source of light module and applying it to a real designing a building-lighting . In the negative aspect that a digital technology can standardize a space for a lighting, a "Interactive-lighting Technique", which detects an analogic change of nature through a sensor and produces it, can become a new alternative one.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.6
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• pp.510-514
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• 2005

We have investigated the excitation-light source dependence of photo-catalytic efficiency for the benzene removal. The photo-catalytic module for the benzene removal is fabricated by a combination of GaN-based ultraviolet light-emitting diode (UV GaN-LED) and $TiO_2$ thin film coated on an aluminum plate. The benzene reduction rates of 365 nm and 375 nm modules at 60 mA junction current are approximately $8.95\;\%/Hr$ and $9.2\;\%/Hr$, respectively, which indicates that 365 nm GaN-LED is more effective than 375 nm GaN-LED. The benzene reduction efficiency is also noticeably dependent on the excitation wavelength and excitation-light power, as well as it is increased with the shorter wavelength and higher excitation power. This result exhibits that UV GaN-LED is useful to remove the volatile organic compounds (VOCs) existing in the environment.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.1-7
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• 2010

LEDs, compared to conventional light sources, have many advantages and their applications are rapidly expanding, especially in areas such as back-lights for LCD. In this paper, we propose a new LED lamp structure suitable for applications requiring a low power. In the proposed LED lamp structures, LED chips are mounted on a transparent polycarbonate plate, and thus photons are transmitted through the both sides of the plate. The copper layer deposited on the polycarbonate plate is patterned to form circuit patten and the chip mount pad, on which LED chips are mounted. We speculate that our proposed LED lamp structures may be used as a type of plate light source.

• 한국정보디스플레이학회:학술대회논문집
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• 2008.10a
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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.

• Korean Journal of Optics and Photonics
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• v.35 no.1
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• pp.18-23
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• 2024

In exhibition spaces such as art museums, lighting should primarily illuminate the walls where exhibits are displayed rather than the floor. Commonly used LED lighting consists of an LED and a diffusion plate that closely resembles a Lambertian light source with uniform light distribution at every angle. This type of illumination focuses on the floor surface where normal incidence occurs. Consequently, this general illumination method is not well-suited for effectively lighting the wall surface. Specifically, to illuminate a wall, it is necessary to increase the light intensity in areas with a large incident angle in the light distribution. In response to this issue, our study proposes an illumination system that uses an ultra wide converter to adjust the divergence angle from the light source to 180 degrees.

• Horticultural Science & Technology
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• v.30 no.6
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• pp.673-679
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• 2012

This study was conducted to examine the effect of artificial light source and photoperiod on the growth of leaf lettuce (Lactuca sativa L.) 'Seonhong Jeokchukmyeon' in a closed-type plant production system. Seedlings were grown under 3 light sources, fluorescent lamp (FL, Philips Co. Ltd., the Netherlands), WL #1 (Hepas Co. Ltd., Korea), and WL #2 (FC Poibe Co., Ltd., Korea), each with 3 photoperiods, 12/12, 18/6, and 24/0 (Light/Dark). An irradiance spectrum analysis showed that FL has various peaks in the 400-700 nm range, while WL #1 and WL #2 have only one monochromatic peak at 450 and 550 nm, respectively. The greatest plant height, fresh and dry weights were obtained in the 24/0 (Light/Dark) photoperiod. The 24/0 (Light/Dark) photoperiod treatment promoted vegetative growth of the leaf area. Length of the longest root, number of leaves, fresh weight, and total anthocyanin contents were greater in FL than in either WL #1 or #2. The greatest chlorophyll fluorescence (Fv/Fm) was found in the 12/12 (Light/Dark) photoperiod with FL treatment. The energy use efficiency of the LED increased by about 35-46% as compared to FL. Results suggest a possibility of LED being used as a substitute light source for fluorescent lamp for lettuce cultivation in a plant factory system.

• Journal of the Korean Institute of Telematics and Electronics
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• v.16 no.4
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• pp.22-26
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• 1979

Microlenses with an extremely small radius of curvature are efficiently use d to couple LED/laser diode light into optica1 fiber. We propose a Tapered lens for the highly efficient coupling of the optical fiber communication light souses into the fiber. Ray optical analysis shows that the maximum coupling efficiency is as high as 90 %, Tapered lens with optimum parameters are fabricated by using heating and pulling technique. Experiment shows that this new technique improves the coupling efficiency by two and four times for LED and laser diode, respectively, as compared with the simple flat - end coupling.