• Title, Summary, Keyword: LED

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InGaN/GaN LED 구조의 Bowing 및 광전특성 개선 연구

  • Lee, Gwan-Jae;Kim, Jin-Su;Lee, Cheol-Ro;Lee, Jin-Hong;Im, Jae-Yeong
    • Proceedings of the Korean Vacuum Society Conference
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    • pp.192.2-192.2
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    • 2015
  • 본 논문에서는 사파이어 기판 표면에 레이저 처리를 통해 격자 구조(레이저 격자 구조)를 제작하고 InGaN/GaN 발광다이오드(Light-Emitting Diodes, LED) 박막을 성장 한 시료에서 Bowing 특성 변화를 논의한다. 그리고 Bowing 정도에 따른 InGaN/GaN LED의 광학 및 전기적 특성을 Photoluminescence (PL)와 Electroluminescence (EL) Mapping 법을 이용하여 상호 비교 분석하였다. 2-인치 사파이어 기판 상에 레이저 격자 구조의 간격은 1 mm (GS1-LED), 2 mm (GS2-LED), 3 mm (GS3-LED) 로 제작하였으며, 격자 구조가 없는 LED를 기준 시료(C-LED)로 사용하였다. GS1-LED, GS2-LED, GS3-LED의 Bowing 정도는 C-LED 대비 각각 8%, 7.6%, 6.4% 감소하였다. PL Mapping 결과, GS-LED의 발광 파장의 분포 균일도가 C-LED 보다 개선되는 것을 확인하였고, 파장이 C-LED 대비 단파장으로 이동하였다. 또한, GS-LED시료의 PL 강도는 C-LED보다 증가하였고, 특히 GS2-LED의 PL 강도는 C-LED 대비 6.9% 증가 하였다. EL mapping 결과, GS-LED 발광 파장의 분포 균일도는 PL 결과와 유사하게 측정되었으며, 2인치 기판 전체 면적에 대한 GS-LED의 주요 동작전압 및 출력 전력 수율이 C-LED대비 현저히 개선되었다. 사파이어 기판 표면에 제작한 레이저 격자 구조에 따른 InGaN/GaN LED의 광학적, 전기적 특성을 Bowing의 개선과 응력 완화 현상으로 논의 할 예정이다.

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A study on the improvement of thermal characteristics of high power light source (고출력 광원의 방열특성 개선에 대한 연구)

  • Lee, Han-myung;Kim, Young-woo;Chun, Woo-young;Kim, Yong-hyung;Kim, Jin-hong
    • Proceedings of the KIEE Conference
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    • pp.1285-1285
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    • 2015
  • 현재 전력난에 의해 에너지 절감이라는 말은 가정 및 산업 현장 곳곳에서 들을 수 있다. 에너지 절감 대책 중 하나가 몇 년전 정부에서 발표한 백열등 수입 및 유통금지가 있다. 그 효과로 LED 산업이 각광 받게 되었다. 다양한 LED 산업 및 기술에서도 신뢰성 및 성능 분야는 항상 진화하고 많은 기업들이 집중하고 있다. LED에서 중요한 요소인 방열성능을 개선시키기 위해 많은 연구를 행하고 있다. 그리고 광원 개발분야에서도, 반도체 광원의 LED PKG의 다량 실장으로 고출력을 행하는 것 보다는 기판위에 Blue Chip을 실장하여 제작하는 고출력 광원의 기술로 집중되고 있다. 이 논문에서는 고출력 광원인 COB(Chip On Board) LED의 방열성능 개선을 다루었다. 기판의 구조 변형으로 방열특성 개선 대안을 제시하였다. Via hole과 Cavity를 이용한 구조를 제안하였다. 그에 대한 해석 방법으로는, 구조적인 해석과 수치적인 해석을 활용하였다. 그 결과로는 약 13~40%의 방열성능 개선을 나타내었다.

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Optimum Designs of 2 Segment LED Reflectors for Various Light Output Distributions on the Surface of an LED Chip (LED 칩 표면 광량 분포 변화에 따른 2단 반사컵의 최적 설계)

  • Yim, Hae-Dong;Lee, Dong-Jin;Kim, Yang Gyeom;Jeong, Jang Hee;Lee, Seung-Gol;O, Beom-Hoan
    • Korean Journal of Optics and Photonics
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    • v.23 no.6
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    • pp.269-273
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    • 2012
  • It is important to control the beam pattern of an LED by the design of a reflector. The optimum conditions of the structure parameters for the 2 segment LED reflector are analyzed and compared as they vary depending on the various intensity distributions of light output on the LED chip surface. It is also interesting that combining various types of reflectors is possible to give several efficient beam patterns, such as the maximum intensity profile or relatively wide controllability of beam angle.

Beam Pattern Analysis of LED Reflector Design and Simplification of the Functional Design (조명용 LED 반사컵의 설계변수 의존도 분석 및 기능성 설계의 단순화 기법)

  • Yim, Hae-Dong;Lee, Dong-Jin;Kim, Yang Gyeom;O, Beom-Hoan
    • Korean Journal of Optics and Photonics
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    • v.23 no.5
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    • pp.222-226
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    • 2012
  • The design methods of the reflecting cup employed in an LED lamp are presented. The beam patterns of an LED lamp can be adjusted by functional segmentation of the reflector height. Thus, the reflecting angle of slope was designed according to the height. The analysis of the designed reflecting cup shows that precise adjustable beam patterns can be achieved.

Development of High power LED module for Channel letter (Channel letter용 High Power LED Module 개발)

  • Kim, Jin-Hong;Song, Sang-Bin;Kim, Gi-Hoon
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.95-100
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    • 2007
  • Channel letter용 High Power LED Module 개발하기 위하여, 1W 백색(단색) LED 1EA LED Module과 1W 백색(단색) LED 3EA LED Module, 3W RGB LED 1EA LED Module에 대한 3종의 제품 개발하고, 고효율 RGB LED SMPS 회로 설계, 광색 가변을 위한 RGB LED 최적 배치 및 렌즈 설계, 고출력 1W LED Module 방열 설계 및 기구 개발, SMPS 회로 및 RGB LED 배열 회로 통합 시제품 직접 제작하였다, 신뢰성 평가 및 성능 시험 등을 실시하였으며, T자형 Channel letter에 기존 고휘도 LED Module과 개발된 고출력 LED Nodule을 동시에 적용한 결과, 기존 고휘도 LED Module를 사용하였을 경우에는 $1W{\times}10$개로 10W의 전력을 소비하였으나 개발된 고출력 LED Nodule은 $3W{\times}3$개로 9W의 전력을 소비하였으며 1W의 에너지가 절감되었음에도 불구하고 평균 휘도는 약 2.5배, 균제도는 1.43 배가 더 우수한 결과를 얻었다.

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Design of the Power-LED Driver for High Speed Dimming Control (고속 디밍제어를 위한 고출력-LED 드라이버 설계)

  • Lee, Keon;Kang, Woo-Seong;Jung, Tae-Jin;Yoon, Kwang-Sub
    • Journal of the Institute of Electronics and Information Engineers
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    • v.50 no.8
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    • pp.128-135
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    • 2013
  • This paper presents a high dimming ratio Power-LED driver IC with high power which is capable of controlling LEDs. In order to accomplish a high dimming ratio LED driver, the preloading inductor current methodology is proposed for the power stage of the proposed method to achieve the fast transient response time during the Power-LED load switching. The information containing the current flowing on the LEDs can be utilized to predict the amount of the current on the inductor. The minimum LED current rising time of existing high dimming ratio Power-LED driver is limited by $3{\mu}s$, however that of the proposed high dimming ratio Power-LED driver is reduced about 1/10. The LED driver is implemented with 0.35um 60V BCDMOS 2-poly 4-metal process. The measurement results show that the proposed LED driver system features the minimum rising time as small as 240ns at the dimming frequency of 1KHz with a 12V of input voltage, nine white LEDs and 353mA of LED current. The LED rising time and power conversion efficiency of the chip are measured to be 240ns and 93.72%, respectively.

A Study on The Photosynthesis Accelerate by Light Color Composition in Plant Factory (식물공장 광원의 색조합에 따른 광합성활성화에 관한 연구)

  • Hong, Ji-Wan
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.11
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    • pp.368-375
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    • 2016
  • This study examined the criteria for efficient LEDs used throughout the experiment of an LED with another light color growth to be used in a plant factory. The experiment was confirmed by measuring the Red-LED, Blue-LED, plant growth, and amount of carbon reduction in a White-LED environment. The white-LED showed a similar growth trend to the Red-LED. Blue-LED showed the lowest growth. Measurements of the carbon dioxide levels, showed that the Red-LED and blue LED produced the lowest levels. The combination of the ratio of the LED showed four Red-LEDs and one blue LED to be the higher of the two. In addition, three Red-LED and one Blue-LED produced equal growth to that of the white-LED. In addition, as much as possible, red is the light color that obtains the result suitable for plant factories.

Development of Wireless Control System for High Power LED Luminaire Using Bluetooth Wireless Communication and Current Control System (Bluetooth 무선 통신과 전류제어 시스템을 이용한 고전력 LED 등기구의 무선제어 시스템 개발)

  • Lee, Wan-Bum
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.3
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    • pp.66-72
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    • 2016
  • An LED lighting control system was developed to combine information technology and LED lights for efficient management and energy savings. The system can monitor and control the status of an LED luminaire using Bluetooth wireless communication, sensor technology, and smart phones. An LED lighting control circuit was designed using a temperature sensor, illumination sensor, and Bluetooth module with a fuzzy constant-current control circuit. We extended the lifetime and prevented damage to the LED by optimizing the supply current of the LED luminaire based on the heat-generation temperature of $70^{\circ}C$ of an LED heat sink. We also automatically adjusted the ON/OFF time depending on the ambient illumination of the LED luminaire. By allowing easy control of the LED luminaires on a smartphone, we improved the efficiency and achieved energy savings. The control system was validated through experiments for normal operation.

A Study on the Modularization of LED Driver for Illumination Using a Fly-Back Converter (플라이백 컨버터를 이용한 조명용 LED Driver의 모듈화 연구)

  • Choi, Jin-Bong;Kim, Kwan-Woo;Jung, Young-Gook;Lim, Young-Cheol
    • The Transactions of the Korean Institute of Power Electronics
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    • v.14 no.6
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    • pp.504-513
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    • 2009
  • This paper proposes the new type LED driver modularization for illumination LED driver. The proposed LED driver circuit insulates a hot GND of AC input power and a cold GND of LED driver part by using a fly-back converter. In order to control easily the current of the LED, the fly-back converter is operated in the discontinuous mode with excellent dynamic characteristics, and the characteristics of the LED are verified after the closed loop control is performed using a KIA2431. The LED driver module allows the wide AC power input ranges and realizes the burst dimming function which directly regulates a PWM control IC. This paper describes the operation principle of the LED driver module and it is proved the usefulness through the real model with experimentation. Besides, this paper proposes the multi-channel LED driver which the miniaturized and modularized LED driver module are connected by parallel, and verified its propriety by experiments.

Analysis of Property for White and RGB Multichip LED Luminaire (백색 LED와 RGB 멀티칩 LED 조명장치의 특성 분석)

  • Jeong, Byeong-Ho;Kim, Nam-Oh;Kim, Deog-Goo;Oh, Geum-Gon;Cho, Geum-Bae;Lee, Kang-Yoen
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.12
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    • pp.23-30
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    • 2009
  • LEDs are increasingly used for many applications including automotive, aviation, display, transportation and special lighting applications. Generally, the RGB multichip LED luminaire applied to signboard, emotional lighting system and display device and the white LED luminaire applied to general lighting system. white LED spectra for general lighting should be designed for high luminous efficacy as well as good color rendering. This paper describes characteristics of LED luminaire white LED and RGB multichip LED. Two type of LED luminaire prototype used experiment physical, electrical and optic test and performance analyzed. RGB multi-chip and phosphor-type white LED luminaire were analyzed by experiment on their color characteristics and luminous efficacy of radiation, distribution curve, and electrical characteristics. Research work is in progress to develop an improved performance for optic and electrical works well for two type of LED luminaires.