• 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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Experimental Demonstration of Micro LED-to-LED Visible Light Communications (Micro LED-to-LED 무선 가시광 통신의 실험적 증명)

  • Kwon, Dong-Yoon;Kim, Sung-Man
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.2
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    • pp.219-226
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    • 2021
  • LED-to-LED VLC is a technology that uses LEDs as both a transmitter and a receiver unlike the typical VLCs. In this paper, we experimentally demonstrate a micro LED-to-LED VLC using Micro LED. We tested all the possible VLC cases using red, yellow, green, blue, and white color LED as both a transmitter and a receiver, and measured rise time and SNR. Then we calculated channel capacity depending on the LED color sets. Our experimental results show that the best channel capacity is 125 kbps when the transmitter micro LED was blue and the receiver LED was green. We also measured BERs of VLCs using OFDM signal, and we showed a successful micro LED-to-LED VLC upto 250 kbps.

A study of violet LED chips and white LED lamps (자색 LED 칩 및 백색 LED 램프에 대한 연구)

  • 서종욱;김창연;김희수;노승정
    • Journal of the Korean Vacuum Society
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    • v.12 no.4
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    • pp.235-238
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    • 2003
  • Conventional LED displays use pixels which consist of red, green and blue LEDs of different operation voltages and degradation characteristics. Thus, the circuits are complicated and the display of each color changes independently with the operated time. In order to solve these drawbacks, an LED chip of a short wavelength and an LED lamp with the mixture of red, green, blue fluorescencers and epoxy on the LED chip were studied. The fluorescencers are excited by the light of the LED chip. The LED chip has an active layer of InGaN, a peak wavelength of 408 nm, a FWHM of 13 nm and the CIE index of (0.198, 0.087). White LED lamps were obtained and the CIE index change was observed with the change of the epoxy amount added to the fluorescencers.

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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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 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.

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.

Improving the QoS using the Modulation and Coding Selection scheme by temperature characteristic of LED in the LED-ID system (LED-ID 시스템에서 LED의 온도 특성에 따른 선택적 변조 및 부호화를 통한 QoS 향상 기법 연구)

  • Lee, Kyu-Jin;Seo, Hyo-Duck;Han, Doo-Hee;Lee, Kye-San
    • The Journal of The Korea Institute of Intelligent Transport Systems
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    • v.12 no.1
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    • pp.66-74
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    • 2013
  • This paper introduces the improvement of QoS to compensate the decreasing LED performance by temperature characteristic in the LED-ID communication system. LED does not only use as a lighting device, but also uses as a communication device. The conventional system is transmitted by RGB of LED following the mixture color ratio, which determined the color of lighting, and the BER performance of each RGB signals. However, when the LED used consistently, it has occurred the heat temperature. As a result, LED is degraded the performance by increased temperature each device. To solve this problem, we proposed the adaptive modulation and coding scheme by temperature of device to improve the performance of system and satisfied the QoS in the LED-ID system.

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.

A Study on LED Fluorescent Lamp applying Circuit Driven Method to Tubular LED Lamp Converter (직관형 LED램프 컨버터에 회로구동방식을 적용한 LED 형광등 연구)

  • Yang, Byongmoon;Cha, Jaesang
    • Journal of Satellite, Information and Communications
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    • v.10 no.1
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    • pp.77-82
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    • 2015
  • In this paper, we perform a study on LED Fluorescent Lamp applying Circuit Driven Method to Tubular LED Lamp Converter. The energy efficiency of LED fluorescent lamp converter requires exceptional protection circuit design, circuit design and structure, because it can not take advantage of Heat-sink structure of the heightened degree Reflector for Fluorescent Lamp. In this paper, we performed a study on LED fluorescent lamp applying circuit driven method to tubular LED lamp converter, Also, we designs LED lamp and converter which can supply DC power common commercial power source.