• 조명전기설비학회논문지
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• 제29권5호
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• pp.26-33
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• 2015

Secondary optical system designed for LED bulb which emits light in all directions was simulated with Energy Star standards. Components of the optical system were LED light source, the cover of the LED bulb and reflector which is to confirm the diffuser plate and LightTools software was used to design the illumination optics. The main points of the secondary optical system design are the location of the LED light source, the shape of the LED bulb cover, the location of the reflection plate, and the scattering properties of the diffusing plate. Mechanism of the LED bulb is that the light emitted from the light source move on to the backward after reflected by the coated light cover from the inside and then the reflected light is scattered by the diffuser plate. The LED bulb was designed to satisfy the standard light distribution and color specifications of the Energy Star(IES LM-79-08).

• Journal of information and communication convergence engineering
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• 제11권4호
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• pp.247-252
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• 2013

An intelligent light emitting diode (LED) dimming system is designed and implemented for energy-saving lighting systems. An LED light bulb is powered by an LED driver controlled by a microcontroller using pulse width modulation (PWM) signals. By changing the duty cycle of the PWM signals, the LED driver generates a driving current of up to 1,000 mA. The current consumption by the LED light bulb exhibits a very linear characteristic that indicates that the level of LED dimming can be finely tuned. Multiple sensors-lighting intensity and ultrasonic range sensors-are combined with the LED dimming system to realize an automatically controllable LED lighting system. The light intensity sensor is capable of sensing ambient light. The ultrasonic range sensor can detect objects from 0.15 to 5.6 m at a resolution of 0.0254 m. The collected information by the light intensity and ultrasonic range sensors is processed by the microcontroller that in turn automatically controls the brightness of the LED light bulb. The algorithm of the software for the LED dimming system is also described.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2009년도 공동학술대회
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• pp.538-539
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• 2009

해양교통안전시설인 등대 불빛은 지금까지 백열전구를 사용한 필라멘트를 이용하여 열을 빛으로 바꾸는 광원을 사용하고 있으며, 점차적으로 저전력 소비 및 장수명의 장점을 가진 고휘도 LED(Light Emitting Diode)을 이용한 LED 도등, LED 등명기, LED 등대 표체 경관조명, LED로 만든 전등 국내 개발 등 차세대 광원 "발광다이오드"는 수년내에 시장을 평정할 것으로 전망된다.

• 원예과학기술지
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• 제34권1호
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• pp.55-66
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• 2016

This study was carried out to investigate the effect of artificial light sources with different light qualities on the growth and flowering characteristics of a herbaceous long-day plant, Petunia ${\times}$ hybrida Hort. Seedlings of petunia cultivar 'Madness Rose' were potted, acclimated for one week, and grown in a phytotron equipped with tube- and bulb-type fluorescent lamps (FL tube and bulb), tube-type white light-emitting diodes (LED tube), halogen lamps (HL), metal halide lamps (MH), and high pressure sodium lamps (HPS) for 10 weeks. The temperature, photoperiod, and photosynthetic photon flux density (PPFD) in the phytotron were $22{\pm}2^{\circ}C$, 16 h, and $25{\pm}2{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$, respectively. Light sources combined with HL promoted stem elongation, and plant height and internode length decreased with increasing red to far-red (R:FR) ratio. FL tube + LED tube, HPS, and FL tube promoted branching, whereas plants grown under light sources combined with HL did not have any branches. Days to flowering (from longest to shortest) occurred as follows: FL tube + HL > FL tube + HL > MH > HPS = FL tube + FL bulb > FL tube + LED tube > LED tube > FL tube, indicating that reducing the R:FR ratio of the light sources promoted flowering. Only 20% of plants grown under an FL tube flowered, whereas under all other treatments, 100% of plants flowered. At 10 weeks after treatment, plants grown under HPS and MH had (cumulatively) 12 open flowers, and those grown under FL tube + FL bulb, LED tube, FL tube + LED tube, and HPS treatment had approximately seven flower buds. These results suggest that light sources with low R:FR ratios promote flowering and stem elongation in petunia, but they reduce its ornamental value due to overgrowth and poor branching.

• 전기학회논문지
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• 제56권7호
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• pp.1261-1267
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• 2007

Although LEDs have been used in various applications with improving the brightness and luminous efficacy, the electrical and optical characteristics of high power LED varies at different temperature and starting time. In this paper, optimal heat sink and apparatus design were conducted using IR camera and ICEPAK on the LED bulb consisting with fourteen LED array. The temperatures of heat sink and LED device of the designed LED bulb without cooling pan were $74^{\circ}C\;and\;96.8^{\circ}C$, respectively, showing in good themal characteristics. For high efficiency driving circuit of LED array adopted optimal heat sink design, driving circuits of constant voltage and current circuits were suggested and fabricated. As a result the efficacy of all driving circuits showed more than 20 lm/W. Also, the constant current circuits are suitable for signal lamp, hallway lamp, and flash lamp having short operating time(about 30 min). On the other hand, a reading light and indoor lamp having long operating time can be controlled by constant voltage circuit.

• 전기학회논문지
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• 제59권11호
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• pp.2043-2047
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• 2010

This study is to solve problems of depletion of RF bandwidth frequency, confusion possibility, security that current wireless communications system have and is to confirm possibility of applying next generation network. To solve problems of current wireless communications system, visible light communications system for power line communications using ATmega16 Microcontroller is was realized and receiver property was analyzed. PLC exclusive chip APLC-485MA, Microcontroller ATmega16, 5pi bulb type LED and high flux LED, visible light receiving sensor LLS08-A1 were used for transmitter and receiver. Performance was analyzed by designed program and an oscilloscope. It was showed average 20% improved receiver rate rather than bulb type LED in the case of high flux LED through voltage change rate on communication distance and LED type of distance between 10 to 50 cm. The blue LED showed the best performance among measured LED types with above 10% of voltage decreasing rate. But As it gradually becomes more distant, the precise date was difficult to obtain due to weak light. To overcome these sort of problems, specific values such as changing conditions and efficiency value relevant to light emitting parts and visible light receiving sensor should be calculated and continuous study and improvements should also be accomplished for the better communications condition.

• 한국환경농학회지
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• 제33권4호
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• pp.358-363
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• 2014

본 연구는 적색광(660 nm)을 이용한 딸기(Fragaria ${\times}$ ananassa Duch. cvs. "Seolhyang")의 일장연장 처리효과를 구명하고자 수행하였다. 포트실험에서 관행의 백열등 40 Lux와 적색광 0.70, 0.87, $1.05{\mu}mol/m^2/s$ (PAR)에 의한 일장연장 처리는 백열등 처리 보다 적색광 강도가 증가할수록 딸기의 초장, 엽수, 과실무게가 증가하는 경향이었다. 재배포장실험에서 적색 LED $0.7{\mu}mol/m^2/s$ 강도의 일장연장처리는 관행의 백열등 40 Lux 처리 보다 딸기의 엽 생체중, 엽병 생체중, 크라운 생체중과 총 생체중을 유의하게 증가시켰다. 적색 LED 처리가 백열등 처리 보다 딸기의 과실수는 5%, 과실무게는 2.9%, 딸기 수확량은 8.5% 증가시키는 경향이었으나 통계적으로 유의한 차이는 나타내지 않았다. 적색 LED 처리는 백열등 처리보다 상품성 있는 15 g 이상의 딸기과실 수를 증가시키는 경향을 보였다. 따라서 딸기의 일장연장을 위한 광원으로 적색 LED도 이용될 수 있을 것으로 기대되며 향후 관련 연구가 계속 수행되어야 할 것으로 판단된다.

• 전기학회논문지
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• 제59권5호
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• pp.996-1000
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• 2010

In order to apply VLC (visible light communication) in harsh environment of nuclear power plant in-containment building, the high luminance LEDs, which are key components of the VLC system, have been gamma irradiated at the dose rate of 4 kGy/h during 72 hours up to a total dose of 288 kGy. The radiation induced coloration effect in the high luminance LED bulb made of acryl or plastic material was observed. In the VLC wireless data transmission experiment using the high luminance LEDs irradiated by high dose rate gamma-ray, the radiation induced coloration effect of the high luminance LED bulb extended the communication distance compared to non-irradiated LEDs.

• Journal of Applied Biological Chemistry
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• 제59권2호
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• pp.129-132
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• 2016

곡물저장창고에서 light emitting diode (LED) 트랩의 실증실험을 통하여 이용 가능성을 검토하기 위하여 어리쌀바구미와 거짓쌀도둑거저리의 유인효과를 평가하였고, 상업적 대조구 black light bulb (BLB) 트랩과 비교하였다. 그 결과 어리쌀바구미와 거짓쌀도둑거저리에 대해 red LED 트랩은 BLB 트랩보다 높은 유인활성을 나타내었으며, 곡물저장창고 외부에서 진행한 실험은 내부 실험보다 약 1.5배 높은 유인활성을 보여주었다. 이러한 결과를 바탕으로 red LED 트랩이 곡물저장창고에서 친환경 저곡해충 방제기술로써 적용 가능성을 보여주었다.

• 한국생산제조학회지
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• 제23권1호
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• pp.64-68
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• 2014

This paper introduces the use of a crown-shaped (CR) lens to effectively diffuse the light from a light-emitting diode (LED) without any loss in the light intensity, in contrast to polymer-bulb-type diffusers. The diffusion lens was designed based on the Snell's law, which describes the physical path of a ray passing through the boundary between different media. CR lenses were fabricated by polydimethylsiloxane (PDMS) casting and UV-embossing processes, which used a pre-designed metal mold and UV-curable resin, respectively. Through experiments and optical evaluations, it was verified that the newly proposed CR lens not only decreased the vertical light strength and glare effect from an LED light source but also improved the diffusion characteristics while maintaining the quality of the LED's light intensity.