• Title, Summary, Keyword: Light-emitting diode

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Analysis of Level Characteristics of 630nm Light Emitting Diode Module (630nm Light Emitting Diode 모듈의 레벨 특성 평가)

  • Kim, Tae-Gon;Cheon, Min-Woo;Park, Yong-Pil;Kim, Seong-Hwan;Song, Chang-Hun;Kim, Young-Su
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.347-348
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    • 2006
  • This paper performed the basic study for developing the Photodynamic Therapy Equipment for medical treatment. The equipment have been manufactured by using the High Bright Light Emitting Diode and TLC5941 integrated circuit. As a result, 630nm Light Emitting Diode Module was made for the optimization of irradiation condition. And we confirmed the current change according to increase of the level of Light Emitting Diode Module.

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Reliability Assessment Criteria of Organic Light Emitting Diode(OLED) (유기 발광 다이오드의 신뢰성 평가기준)

  • Hong, Won-Sik;Song, Byeong-Suk;Jeong, Hai-Sung;Lim, Jae-Hak
    • Journal of Applied Reliability
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    • v.9 no.2
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    • pp.131-148
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    • 2009
  • An organic light emitting diode (OLED), also light emitting polymer (LEP) and organic electro luminescence (OEL), is any light emitting diode (LED) whose emissive electroluminescent layer is composed of a film of organic compounds. The layer usually contains a polymer substance that allows suitable organic compounds to be deposited. They are deposited in rows and columns onto a flat carrier by a simple "printing" process. The resulting matrix of pixels can emit light of different colors. Such systems can be used in television screens, computer displays, small, portable system screens such as cell phones and PDAs, advertising, information and indication. OLEDs can also be used in light sources for general space illumination, and large-area light-emitting elements. In this paper, we develop the general guide line of the accelerated life test for assuring B10 life of AMOLED(Active Matrix Organic Light Emitting Diode) and PMOLED(Passive Matrix Organic Light Emitting Diode) which are widely used for display monitor less than 115 mm.

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Cultivation of Chlorella sp. under Different Aeration Conditions Illuminated by Light Emitting Diode (LED 조명을 이용한 광생물 반응기에서 공기 주입량에 따른 클로렐라 성장 연구)

  • Choi, Bo-Ram;Lee, Tae-Yoon
    • KSBB Journal
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    • v.27 no.4
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    • pp.263-267
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    • 2012
  • The purpose of this study was to determine optimum value of aeration rate for the cultivation of Chlorella sp. under illumination of red light emitting diode. The aeration rates varied from 0 to 2.4 vvm under the illumination of 4,400 lux of red light emitting diode. The highest specific growth rate of $1.51\;day^{-1}$ was obtained at the aeration of 0.7 vvm and lower specific growth rates were obtained for other aeration tests. Furthermore, the highest biomass concentration (1.02 g/L) was also obtained at the aeration of 0.7 vvm. Therefore, aeration of 0.7 vvm was determined to be the optimum aeration rate for the cultivation of Chlorella sp. under red light emitting diode.

Interfacial Engineering of Polymer Light Emitting Diode

  • Chen, Show-An
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.165-167
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    • 2007
  • The performance of polymer light emitting diode can be improved significantly by interfacial engineering on anode and/or cathode through adjusting the charge injection barriers for holes and electrons. Studies involve CFx and SAM modifications on ITO, thickness and delay time to baking of PEDOT:PSS, and electron injection/hole blocking layer.

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The Verification of Photoplethysmography Using Green Light that Influenced by Ambient Light (녹색광을 이용한 반사형 광용적맥파측정기의 주변광 간섭시 신호측정)

  • Chang, K.Y.;Ko, H.C.;Lee, J.J.;Yoon, Young Ro
    • Journal of Biomedical Engineering Research
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    • v.35 no.5
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    • pp.125-131
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    • 2014
  • The purpose of this study is to verify the utility of reflected photoplethysmography sensor using two green light emitting diodes that influenced by ambient light. Recently it has been studied that green light emitting diode is suitable for light source of reflected photoplethysmography sensor at low temperature and high temperature. Another study showed that, green light is better for monitoring heart rate during motion than led light. However, it has a bad characteristic about ambient light noise. To verify the utility of reflected photoplethysmography sensor using green light emitting diode, this study measures the photoplethysmography signal that is distorted by ambient light and will propose a solution. This study has two parts of research method. One is measurement system that composed sensor and board. The sensor is made up PE-foam and Non-woven fabric for flexible sensor. The photoplethysmography signal is measured by measurement board that composed high-pass filter, low-pass filter and amplifier. Ambient light source is light bulb and white light emitting diode that has three steps brightness. Photoplethysmography signal is measured with lead II electrocardiography signal at the same time and it is measured at the finger and radial artery for 1 minute, 1000 Hz sampling rate. The lead II electrocardiography signal is a standard signal for heart rate and photoplethysmography signal that measured at the finger is a standard signal for waveform. The test is repeated 3 times using three sensor. The data is processed by MATLAB to verify the utility by comparing the correlation coefficient score and heart rate. The photoplethysmography sensor using two green light emitting diodes is shown better utility than using one green light emitting diode and red light emitting diode at the ambient light. The waveform and heart rate that measured by two green light emitting diodes are more identical than others. The amount of electricity used is less than red light emitting diode and error peak detectability factor is the lowest.

Electrical Conduction Mechanism and Equivalent Circuit Analysis in $Alq_3$ based Organic Light Emitting Diode ($Alq_3$에 기초한 유기 발광 소자에서 전기전도특성과 등가회로분석)

  • Chung, Dong-Hoe;Shin, Cheol-Gi;Lee, Dong-Gyu;Lee, Joon-Ung;Lee, Suk-Jae;Lee, Won-Jae;Jang, Kyung-Wook;Kim, Tae-Wan
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.103-106
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    • 2004
  • We have studied a conduction mechanism and equivalent circuit analysis in $Alq_3$ based Organic Light Emitting Diode. The conduction mechanism in organic light emitting diode can be classified into three regions; ohmic region, space-charge-limited current (SCLC) region and trap-charge-limited current (TCLC) region depending on the region of applied voltage. Equivalent circuit model of organic light emitting diode can be established using a parallel combination of resistance $R_p$ and capacitance $C_p$ with a small series resistance $R_s$.

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Study of White Polymer Electrophosphorescent Light-emitting Diode with Heteroleptic Ir-Complex

  • Lee, Jay-Woo;Kim, Eu-Gene
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.648-650
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    • 2007
  • We demonstrate highly efficient White Polymer Electrophosphorescent Light-emitting Diode using newly developed green and red light emitting heteroleptic iridium complex, Ir-(pq)2tpy, and blue light emitting fluorescent dopant, BczVBi. The best luminous efficiency reached 28cd/A with maximum luminance of 87000cd/m2. The scheme for determining optimum device architecture and dopant concentrations were constructed.

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BGR mixture phosphor for white-light-emitting diode of liquid crystal display backlight

  • Lee, Sung-Hoon;Park, Je-Hong;Seo, Kwang-Il;Kim, Jong-Su
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.1559-1560
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    • 2007
  • BGR mixture phosphor pumped by 400 nm is developed for white-light-emitting diode of liquid crystal display backlight. White-emitting phosphor is prepared by mixing $Ba_2SiO_4:Eu^{2+}$ and $(Ba,Sr)_3MgSi_2O_8:Eu^{2+},Mn^{2+}$ phosphors.

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A study on the Characteristics of the Polymer Light Emitting Diode (Polymer Light Emitting Diode(PLED)의 특성에 관한 연구)

  • Moon, H.D.;Kim, H.Y.;Kwon, Y.H.;Kim, Y.H.
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.1082-1085
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    • 2003
  • 본 연구에서는 고분자를 사용하여 만든 유기EL소자인 PLED (Polymer Light Emitting Diode)의 제조공정 변화에 따른 소자성능을 연구하였다. PLED의 제작은 크게 ITO 기판 제작, 발광층 및 전극 증착 등의 공정으로 나누어진다. ITO 기판은 사진식각공정으로, 발광층의 증착은 스핀코팅법으로, 전극은 진공증착법으로 각각 제작하였다. 코팅 시 스핀속도 및 점도 조절을 통하여 발광층의 두께를 조절하였고, 스핀코팅 후 건조방법에 따라서 표면의 uniformity와 발광특성을 비교해 보았다. 실험결과 특정 두께에서 발광특성이 우수하게 나타나는 것을 확인할 수 있었다. 그리고 건조방법에 따라 발광층의 표면 uniformity에 차이가 있었으며, 표면 uniformity에 따라 diode의 I-V 특성 경향이 달리 나타났다.

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Evaluation of green light Emitting diode with p-type GaN interlayer (P형 GaN 중간층이 삽입된 녹색 발광다이오드 특성 평가)

  • Kim, Eunjin;Kim, Jimin;Jang, Soohwan
    • Korean Chemical Engineering Research
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    • v.54 no.2
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    • pp.274-277
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    • 2016
  • Effects of interlayer insertion between multi-quantum well and electron blocking layer of green light emitting diode on diode performances were studied by device simulation. Dependence of Mg doping depth on characteristics of current-voltage, emitting wavelength, leakage current, and external quantum efficiency was investigated, and the optimum diode structure was presented. Device structures with interlayers doped in entire region and up to 30 nm showed remarkable reduced leakage current and effectively relieved efficiency droop which is one of the biggest challenges in green light emitting diode. Furthermore, the most improved characteristics in current-voltage and electroluminescence was obtained by the latter structure.