• Title/Summary/Keyword: High-Power LED

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Development of Fin Expansion Type Cooling System using Heat Pipes for LED Lightings (히트파이프를 적용한 LED조명용 핀확장형 냉각시스템 개발)

  • Jung, T.S.;Kang, H.K.
    • Transactions of Materials Processing
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    • v.21 no.2
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    • pp.131-137
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    • 2012
  • With the advantages of power savings, increased life expectancy and fast response time over traditional incandescent bulb, LEDs are increasingly used for many applications including automotive, aviation, display, and special lighting applications. Since the high heat generation of LED chips can reduce service life, degrade luminous efficiency, and cause variation of color temperature, many studies have been carried out on the optimization of LED packaging and heat sinks. In this study, a fin expansion type cooling device using heat pipe, instead of a solid aluminum heat sink, was designed for LED security lightings based on thermal resistance analysis. Numerical analysis and experimental validation were carried out to evaluate its cooling performance.

An Optical Feedback System for 2D Dimming RGB LED Backlight

  • Lee, Tae-Wook;Lee, Jae-Ho;Kim, Chang-Gone;Kang, Sin-Ho
    • 한국정보디스플레이학회:학술대회논문집
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    • 2008.10a
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    • pp.769-772
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    • 2008
  • For several years, many researchers have proposed LED backlight dimming technology for low power consumption and high contrast ratio. One of the major issues plaguing RGB LED with 2D dimming technology is color shift. This undesirable variation makes it difficult to use RGB LED as light sources in the backlight system. This paper describes the useful method of the optical feedback system for 2D dimming RGB LED backlight. The test results show that our proposed method is very suitable for the 2D dimming technology.

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A Design of LED Lighting Controller for use of Solar Battery (태양전지 이용을 위한 LED 조명 제어기 설계)

  • Kim, Byun-Gon;Lee, Ok-Jae
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.6
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    • pp.18-27
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    • 2011
  • LED lighting because of high efficiency, long life, friendly environment, as a general lighting of the next generation, has been substituted for incandescent bulb and fluorescent lamp. The proposed system for use of solar battery is the intelligent controller for LED street lights which is improved the method of battery charging and charging efficiency in winter to extend battery life cycle, controlled lighting current according to SoC and in steps. Also, it is implemented emotional lighting which is controlled with the surrounding environment, by using colorful sub LED to take up 10[%] of a source of total light, white LED. As a lab results, the proposed system was implemented functions to adapt to the environmental changes, and improved the charging efficiency and battery life cycle.

A Study on the Marine Lattern Development using Light Emitting Diodes (해상용 LED(Light Emitting Diode) 등명기 연구개발)

  • Jeong, Hak-Geun;Jung, Bong-Man;Han, Su-Bin;Yu, Seong-Won;Kim, Hoon
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2004.05a
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    • pp.167-170
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    • 2004
  • A high light lantern system using LEDs is composed of power supply, flash controller, and daylight controller and proper case considering work condition. The performance of developed LED lantern is better than that of the existing marine lantern using an incandescent electric lamp and that of foreign products(Vega LED lantern made in New Zealand, Tideland system made in America). The electric consumption of our products is 30% compared with that of existing marine lantern using an incandescent electric lamp, and the luminous Intensity of them is 200% to 400% compared with that of existing marine lantern and foreign LED lantern. In addition, our LED lantern system is easy to repairing something wrong and changing the LED module and other controllers on the sea when they are in accident.

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Implementation of Visible Light Communication System Modulated by a Switching Driver Circuit of Lighting LED (조명용 LED의 스위칭 구동 회로로 변조되는 가시광 통신 시스템의 구현)

  • Cho, Sang-Ho;Han, Sang-Kyoo;Roh, Chung-Wook;Hong, Sung-Soo;Jang, Byung-Jun
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.21 no.8
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    • pp.905-910
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    • 2010
  • In this paper, visible light communication(VLC) system modulated by a switching driver circuit of lighting light emitting diode(LED), not only for illumination but also for optical wireless communication, is implemented. Presented system could overcome the drawbacks of prior linear modulation technique such as low efficiency, heat generation, and limits to realization of high power lighting LED. Experimental results from the realized digital audio system are presented to confirm the superiority of the proposed circuit. Our prototype achieves a transmission data rate of 10 Mbps with a radius of 1.5 meters using 20 W output power, and the signals were detected successfully.

Delta Sigma Modulation of Controller Input Signal for the LED Light Driver (시그마 델타 변조에 의한 LED 드라이버의 입력 콘트롤러 설계)

  • Um, Kee-Hong
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.2
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    • pp.151-155
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    • 2016
  • In this paper, we present the LED dimming control system by using ADPCM (Adaptive Differential Pulse Code Modulation). This ADPCM apparatus accurately controls the LED current with high resolution reducing the RFI (radio frequency interference) due to the spreading out of the harmonics of current of pulses. Additionally, this makes it easier to increase the accuracy of control operation. This study introduces to make a digitally controlled circuit for controlling LED with high-energy efficient by adopting pulse current to LED. The LED current drive system we designed are two systems, the digitally-controlled unit and analog switching mode power supply unit, can be developed separately. The simulation shows the sigma delta modulation of digital to analog converter's output when the input level is 0.7. From this simulation, the output is approached to accurately 0.15% to target value with 510 pulses.

Implementation of a Ad-Hoc based LED-IT-Sensor Integrated Streetlight with Selective Remote Control (선택적 원거리 점멸이 가능한 Ad-Hoc 기반의 LED-IT-센서 통합 가로등 시스템 개발)

  • Oh, Sun-Jin
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.11 no.5
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    • pp.19-25
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    • 2011
  • With the issue of a Green IT Technology, studies on a environment-friendly luminous source that can reduce Carbon discharge and increase energy efficiency are actively progressed all over the world. Especially, with the problems of high oil price and environmental pollution, LED has made a great attention as a new luminous source that can replace the existing incandescent bulbs and fluorescent lights. In this paper, the proposed streetlight system becomes more intellectual by combining the low power consuming, high efficient, and high luminous LED module with a complex sensor module with temperature, humidity, illumination and motion sensors. Then, we design and implement the Ad-Hoc based LED-IT-Sensor integrated streetlight system that can maximize the energy savings efficiently with central monitoring system and selective remote dimming control by connecting them to the wireless ubiquitous sensor network(USN) using a Zigbee module.

A case study of life cycle cost analysis on high pressure sodium lamp and LED lamp for tunnel lighting (터널 조명 고압나트륨램프와 LED램프의 LCC 분석 사례 연구)

  • Lee, Gyu-Phil;Kim, Jeong-Heum
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.23 no.5
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    • pp.315-323
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    • 2021
  • Tunnel is the most energy-consuming structure in road due to the characteristic of using artificial lighting during day and night. Therefore, tunnel lights are being replaced by LED lamp that have advantages with respect to low power consumption. The best use of social overhead capital can be expected by considering the life cycle cost, because to tunnel structures are accompanied by a series of medium-to-long-term and continuous processes of replacing auxiliary facilities. In this study, the saving effect by LCC analysis was quantitatively analyzed by replacing tunnel light sources from high-pressure sodium lamps to LED lamps. The effect of reducing the replacement cycle by increasing the life of the lamps and the resulting maintenance cost is very significant, on replacing tunnel lighting light sources with LED lamp.

Evaluation of Light Intensity and Uniformity of LEDs for Protected Crop Production

  • Kim, MunJung;Choo, YounKug;Kim, YongJoo;Chung, SunOk
    • Agribusiness and Information Management
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    • v.6 no.1
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    • pp.37-44
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    • 2014
  • This study was conducted to evaluate light intensity and uniformity of two SMD (surface-mount device) type LEDs for protected crop production. A low-power (0.1 W) and a high-power (1 W) LEDs were selected and the intensity and uniformity was evaluated at different vertical (height) and horizontal (distance) intervals. When the horizontal interval of the LED bar was fixed, the light intensity increased and the uniformity decreased as the height decreased. At the 30~40 cm heights, 20~30% of the area showed $200{\pm}20{\mu}molm^{-2}s^{-1}$. As the horizontal distance of the LED bars increased, while the uniformity increased as well, the light intensity decreased. At the distances of 6~10 cm, 17~23% of the area showed $200{\pm}20{\mu}molm^{-2}s^{-1}$. When the LED bars were added to the sides, the light intensity and uniformity were generally improved. Results showed that the light intensity and uniformity depended on the height and interval of the LED bulbs; therefore, optimum arrangement for the crops interested should be determined through experiments.

Cooling Performance Study of a Impinging Water Jet System with Heat Sink for High Power LEDs (분사냉각모듈 내에 부착된 히트싱크에 따른 고출력 LED의 냉각성능에 관한 연구)

  • Ku, G.M.;Kim, K.;Park, S.H.;Choi, S.D.;Heo, J.W.
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.12 no.6
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    • pp.152-158
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    • 2013
  • The purpose of this study is to investigate cooling performance of high power LEDs from 100 to 200 W class by using a jet impingement cooling module. The numerical analysis of forced convection cooling inside cooling module is carried out using a multi-purpose CFD software, FLUENT 6.3. In the experiments, the LED cooling system consists of jet impingement module, heat exchanger, water reservoir, and pump. In the present study, the cooling performance of jet impingement cooling module is investigated to determine the effect of the heat sink types on the impinging surface, the space and length of fins. Numerical and experimental studies show the reasonable agreement of LED metal PCB temperature between those results and give the optimized design parameters such as the space of fin and the length of fin. Also, the pin fin type of heat sink is found to be more efficient than the plate type heat sink in jet impingement cooling.