• Title, Summary, Keyword: LED(Light Emitting Diode)

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Study on the Thermal Dissipation Characteristics of 16-chip LED Package with Chip Size (16칩 LED 패키지에서 칩 크기에 따른 방열특성 연구)

  • Lee, Min-San;Moon, Cheol-Hee
    • Journal of the Korean Vacuum Society
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    • v.21 no.4
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    • pp.185-192
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    • 2012
  • p-n junction temperature and thermal resistance of Light Emitting Diode (LED) package are affected by the chip size due to the change of the thermal density and the external quantum efficiency considering the heat dissipation through conduction. In this study, forward voltage was measured for two different size LED chips, 24 mil and 40 mil, which consist constitute 16-chip package. p-n junction temperature and thermal resistance were determined by thermal transient analysis, which were discussed in connection with the electrical characteristics of the LED chip and the structure of the LED package.

Attractive Effects Efficiency of LED Trap on Controlling Plutella xylostella Adults in Greenhouse (LED 트랩을 이용한 온실내 배추좀나방에 대한 유인효과)

  • Park, Jun-Hwan;Lee, Sang-Min;Lee, Sang-Guei;Lee, Hoi-Seon
    • Journal of Applied Biological Chemistry
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    • v.57 no.3
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    • pp.255-257
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    • 2014
  • This study was conducted to determine the attractive effects of Plutella xylostella adults to light emitting diode (LED) trap in greenhouse and compared with those of no light trap and black-light which is typically used in commercial luring lamp. The green LED trap captured more P. xylostella when compared with black-light trap, whereas the no light trap was a little attractive to P. xylostella adults. These results indicated that the green LED traps could be used for environmental insect pest control.

Analysis on the Luminous Efficiency of Phosphor-Conversion White Light-Emitting Diode

  • Ryu, Han-Youl
    • Journal of the Optical Society of Korea
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    • v.17 no.1
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    • pp.22-26
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    • 2013
  • The author analyzes the luminous efficiency of the phosphor-conversion white light-emitting diode (LED) that consists of a blue LED chip and a yellow phosphor. A theoretical model is derived to find the relation between luminous efficiency (LE) of a white LED, wall-plug efficiency (WPE) of a blue LED chip, and the phosphor absorption ratio of blue light. The presented model enables to obtain the theoretical limit of LE and the lower bound of WPE. When the efficiency model is applied to the measured results of a phosphor-conversion white LED, the limit theoretical value of LE is obtained to be 261 lm/W. In addition, for LE of 88 lm/W at 350 mA, the lower bound of WPE in the blue LED chip is found to be ~34%. The phosphor absorption ratio of blue light was found to have an important role in optimizing the luminous efficiency and colorimetric properties of phosphor-conversion white LEDs.

Growth of Ulva pertusa Kjellman (Chlorophyta, Ulvophyceae) by a Light-Emitting Diode (LED) Light Source (발광다이오드(LED) 조명을 이용한 녹조 구멍갈파래(Ulva pertusa)의 생장)

  • Kwon, Chun Jung;Choi, Chang Geun
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.46 no.5
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    • pp.571-574
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    • 2013
  • To determine an efficient growth system for algal cultivation and to develop adequate culture system utilizing LED light, we investigated the effects of fluorescent and light emitting diode (LED) light source on the growth of Ulva pertusa. U. pertusa was cultured at $17^{\circ}C$ under a light intensity of 35 ${\mu}mol$ photons $m^{-2}s^{-1}$ and a 10L:14D photoperiod using either fluorescent or LED lamps. After 1 week of incubation under the same environmental condition, the length and width of Ulva pertusa grown under LED light were 1.5- and 1.9-fold greater, respectively, than the length and width of algae grown under fluorescent light. After two weeks, length and width were 2.6- and 2.0-fold greater, respectively, in algae grown under LED light. Total length and width of Ulva pertusa after three weeks of incubation were 1.7- and 1.2-fold greater in algae grown under LED light than those grown under fluorescent light. Therefore, the LED light induced significantly higher growth of Ulva pertusa than fluorescent light.

A Study on Characteristics of Light Emitting Diode with Porous Silicon (다공성 실리콘을 이용한 LED의 발광 특성에 관한 연구)

  • Lee Sung-Hoon;Lee Chi-Woo
    • Journal of the Korean Electrochemical Society
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    • v.3 no.1
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    • pp.39-43
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    • 2000
  • The light emitting diode (LED) was fabricated from n-type porous silicon. We investigated both the current-voltage characteristics of the LED with various electrode materials and changes of electroluminescence with applied current density. Also we probed changes in electroluminescence as a function of operation time at a given current. In order to Improve the contact area between the electrode material and porous silicon layer, we deposited indium on porous silicon layer by electroplating and investigated the electric characteristics of the LED and changes of electroluminescence.

Study on Simulation Design of Light Emitting Diode Luminaires for 100 W Safety Street Lighting

  • Shin, Ik-Tae;Lee, Se-Il;Yang, Jong-Kyoung;Park, Dae-Hee;Lee, Dong-Jin
    • Transactions on Electrical and Electronic Materials
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    • v.11 no.3
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    • pp.138-144
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    • 2010
  • Optical analysis is necessary to optimize light emitting diode (LED) safety street lighting. In this study, optical analysis was conducted for 100 W LED safety street lighting. Experimental research on such a single LED was the first undertaken. Simulation modeling based on the optical properties of the single LED has compared between average road illuminances and has them analyzed with Korean Industrial Standards for LED safety street lighting (KS C7658:2009). The simulation results demonstrated that the illumination performance (average road illuminance) was 75.3 lx at a height of 4 m and an area of $32\;m^2$, 45.25 lx at a height of 5 m and an area of $72\;m^2$, and 30.05 lx at a height of 6 m and an area of $128\;m^2$. 100 W safety street lighting (model CE180-ST-OS) designed by simulation was also compared between product and 100 W simulation modeling, and error rates averaged 5.6%. The 100 W LED safety street lighting base designed in simulation modeling was proven by comparison experiments. Through the simulations and the corresponding analysis, it was found that the tested 100 W LED safety street lamp had reasonable performance. The design method for LED safety street lamps has been summarized based on the optical analysis.

Thermal Characteristics: Gap of LED Devices and LED's Lighting Application

  • Liu, Muqing;Zhang, Wanlu;Zhu, Xiaojing
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1347-1348
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    • 2008
  • The efficacy and its degradation of light emitting diode(LED) are related to its PN junction's temperature(Tj). Currently efficacy in certain temperature and thermo-resistant are defined for the depending. However, the definitions are quite inconvenient for lighting application. The paper focuses on the issue and presents a method to evaluate the thermal characteristics of LED efficay.

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An Estimation Method for the Efficiency of Light-Emitting Diode (LED) Devices

  • Tao, Xuehui;Yang, Bin
    • Journal of Power Electronics
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    • v.16 no.2
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    • pp.815-822
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    • 2016
  • The efficiency of light-emitting diode (LED) devices is a significant factor that reflects the capability of these devices to convert electrical power into optical power. In this study, a method for estimating the efficiency of LED devices is proposed. An efficiency model and a heat power model are established as convenient tools for LED performance evaluation. Such models can aid in the design of LED drivers and in the reliability evaluation of LED devices. The proposed estimation method for the efficiency and heat power of LED devices is verified by experimentally testing two types of commercial LED devices.

The shear bond strength and adhesive failure pattern in bracket bonding with different light-curing methods (브라켓 접착시 광중합방식에 따른 전단결합강도와 파절양상 비교)

  • Shin, Jai-Ho;Lim, Yong-Kyu;Lee, Dong-Yul
    • The korean journal of orthodontics
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    • v.34 no.4
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    • pp.333-342
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    • 2004
  • The purpose of this study was to evaluate the clinical effectiveness of a plasma arc light and light emitting diode (LED), compared with shear bond strength and the failure pattern of brackets bonded with visible light in direct bonding. Brackets were bonded with Transbond XT to 60 human premolars embedded in the resin blocks according to different light-curing methods. Then, the shear bond strength of each group was measured using a universal testing machine (Instron) and the adhesive failure pattern after debonding was visually examined by light microscope. The results were as follows: 1. The shear bond strength showed no significant difference between the visible light and light emitting diode, but the plasma arc light exhibited a significantly lower shear bond strength compared with the visible light and light emitting diode. 2. In the visible light and light emitting diode, adhesive failure patterns were similar. Bond failure occurred more frequently at the enamel-adhesive interface. 3. The bonding failure of brackets bonded with plasma arc light occurred more frequently at the bracket-adhesive interface. The results of this study suggest that plasma arc light, light emitting diode and visible light are all clinically useful in the direct bonding of orthodontic brackets.

LED IT-based System sensor network transceiver module research (LED IT 기반 시스템 센서 네트워크 송수신 모듈 연구)

  • Jang, Tae-Su;Lee, Jun-Myung;Choi, Jung-Won;Kim, Yong-kab
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.11-12
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    • 2012
  • In this paper, efficient visible light communication technology LED (Light Emitting Diode) lighting through the existing infrared sensor used for performance analysis of transmitting and receiving is possible. LED utilizes lighting by changing light into electricity. Lighting features while maintaining the basic principles of flashing LED and PD (Photo Diode) to send and receive communications from LED lighting communication convergence principle be realized simultaneously enabling. Multiple IT applications under the basic structure of LED technology development, and the current was encountered in real life. LED lighting anywhere with wireless communication technology that can, in order to ~ 1m above the initial value by taking advantage of the system H/W and infrared sensors(PD) are widely used in the entire system that can improve the speed of visible light data transmission system is finished. LED module that is used to communicate whether the performance analysis, For forecasting and communication distance on the LED and infrared sensor configuration of the implementation of the research is to study about the possibility of application methods and indicates.

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