• Title/Summary/Keyword: Light Emitting System

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Wide Color Gamut Backlight from Three-band White LED

  • Kim, Il-Ku;Chung, Kil-Yoan
    • Journal of the Optical Society of Korea
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    • v.11 no.2
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    • pp.67-70
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    • 2007
  • A Wide Color Gamut Backlight system was studied using a three-band white Light-Emitting Diode. A three-band white light-emitting diode (LED) was fabricated using an InGaN-based blue LED chip that emits 445-nm blue peak, and a green phosphor and red phosphor that emit 535-nm green and 621-nm red peak emissions, respectively, when excited by 450-nm blue light. Using for this three-band white LED, wide color gamut backlight unit (BLU) was attained. The luminance of BLU and CIE 1931 chromaticity coordinates was $1,700Cd/m^2$ and (0.337, 0.346). Color filter matching simulations for this configuration show that the three-band white LED backlight can be enhanced by up to 16% over conventional white LED backlight color gamut.

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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The Study of lantern-lighting in navigational aids system and the view of its hereafter technical development (광파표지 등광에 관한 고찰과 향후 기술개발에 대한 전망)

  • 권혁동;홍태호;박계각
    • Proceedings of KOSOMES biannual meeting
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    • 2003.05a
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    • pp.117-123
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    • 2003
  • It is impossible to apply present standards and test methods because the radiation principle and mechanism of a new marine lantern using light emitting diodes is different from those of the existing marine lantern which uses an incandescent electric lamp. Thus. in this study, we discuss the research and development on the light emitting diodes marine lantern and specifications.

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Light Emitting Polymer Displays

  • Heeks, Karl;Smith, Euan;Goodchild, Bill;Burroughes, Jeremy;Towns, Carl
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.319-324
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    • 2002
  • We will report the latest developments in light emitting polymer (LEP) systems developed at CDT. Device performance for spin coated and ink jet printed systems will be described which are state-of-the-art. We will also report on novel driving schemes for both active and passive addressed LEP displays. These drive schemes extend system lifetime as well as lowering power consumption.

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LED visible light communication and their application (LED 가시광 통신시스템과 그 응용)

  • Chung, Wan-Young;Seo, Yong-Su;Kim, Jong-Jin;Kwon, Tae-Ha
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.14 no.6
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    • pp.1375-1381
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    • 2010
  • LED(Light Emitting Diode) is an emitting device which energy is same to the bandgap energy of p-type and n-type semiconductor junction. Recently high brightness LED is used in fish-luring light and traffic signal light alternative of normal light bulb, and widely used in the area of display pannel. Moreover nowadays LED has been used as a back light of LCD display. Recently, visible light communication(VLC) using LED, that allow two-way serial data communication between LEDs over a distance of sveral centimeters or meters, has been widely studied in the area of digital information transmission along with illumination and display. In this paper, we present LED communication system and their applications.

Behavioral Monitoring System for Mud Shrimp Upogebia major and the Photoresponse to Illumination with Different Wavelength LEDs (쏙(Upogebia major)의 광반응 분석시스템 구축과 발광다이오드(Light-Emitting Diode) 파장별 행동분석)

  • Jang, Jun-Chul;Chung, Jong-Kyun;Hur, Youn-Seong;Song, Jae-Hee;Kim, Jong-Myoung
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.50 no.4
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    • pp.413-420
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    • 2017
  • The increase in the number of mud shrimps Upogebia major is a concern because of their negative effects on shellfish aquaculture, including Manila clam Venerupis philippinatum along the west coast of Korea. This study developed a behavioral analysis system for aquatic animals using a set of monochromatic light-emitting diode (LED) modules covering the visible light range at similar intervals. Movements of mud shrimp were monitored using a tracking system under illumination with infra-red light and an LED of 660 nm wavelength without provoking stimulation. The minimum light intensity needed to induce a photoresponse by the mud shrimp was $10{\mu}mole/m^2/s$ under the conditions tested. Of the six kinds of LED illuminations tested, the most sensitive response was obtained with illumination with the 505 nm LED, followed in order by LEDs with peak wavelengths of $525nm{\fallingdotseq}465nm$ > $405nm{\fallingdotseq}590nm$ > 660 nm. These findings should help to identify LED sources that efficiently induce movement of the mud shrimp and also for monitoring movement without stimulating.

Effects of Various Intensities and Wavelengths of Light Emitting Diodes (LEDs) on the Growth of the Prasinophytes Tetraselmis suecica and T. tetrathele (담녹조강 Tetraselmis suecica 및 Tetraselmis tetrathele의 생장에 미치는 발광다이오드(Light-Emitting Diodes; LEDs) 광량과 파장의 영향)

  • Han, Kyong Ha;Oh, Seok Jin
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.51 no.1
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    • pp.64-71
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    • 2018
  • This study was conducted to investigate the effects of light intensity and wavelength on the growth of Tetraselmis suecica and Tetraselmis tetrathele. These species were exposed to a blue light-emitting diode (LED; max=450 nm), a yellow LED (max=590 nm), a red LED (max=630 nm) and a fluorescent lamp (three wavelengths). The maximum growth rates (${\mu}_{max}$) of T. suecica and T. tetrathele under a red LED were 1.12/day and 0.95/day, respectively. Under a yellow LED, growth rates were 70% of the values for red wavelength, with low half-saturation constants (Ks). The optimum light source to ensure economically effective and productive growth in a Tetraselmis culture system (Photo-Bioreactor) would thus appear to be a three-phase culture, wherein a yellow LED is used during the lag phase and initial exponential phase to increase growth rate, followed by a red LED during the middle exponential phase to maximize growth rate, and finally a yellow LED again during the late exponential phase and stationary phase to achieve increased yield of useful bioactive substances.

Three White Organic Light-emitting Diodes with Blue-green Fluorescent and Red Phosphorescent Dyes

  • Galbadrakha, Ragchaa;Bang, Hwan-Seok;Baek, Heume-Il;Lee, Chang-Hee
    • Journal of Information Display
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    • v.9 no.3
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    • pp.23-27
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    • 2008
  • This paper reports that well-balanced white emission with three primary colors can be achieved with a simple white organic light-emitting diode (WOLED) structure of ITO / $\alpha$-NPD (50 nm) / $\alpha$-NPD: Btp2Ir(acac) (8 wt%, 6 nm) / $\alpha$-NPD (5 nm) / BCP (3 nm) / $Alq_3$: C545T (0.5 wt%, 10 nm) / $Alq_3$ (40 nm) / LiF (0.5 nm) / Al (100 nm). The external quantum efficiency of the device reached 3.8% at a current density (luminance) of 4.6 mA/$cm^2$ (310 cd/$m^2$), and the maximal luminance of the device reached 19,000 cd/$m^2$ at 11.5 V. The insignificant blue shift of the emitting color with an increasing current density can be attributed to the narrowing of the exciton formation zone width.

Emission Characteristics of White Organic Light-Emitting Diodes Using Micro Lens Array Film (Micro Lens Array Film을 이용한 백색 OLED의 발광 특성)

  • Chun, Hyun-Dong;Na, Hyunseok;Yang, Jae-Woong;Ju, Sung-Hoo
    • Journal of the Korean institute of surface engineering
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    • v.46 no.2
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    • pp.93-97
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    • 2013
  • We studied the emission characteristics of white phosphorescent organic light-emitting diodes (PHOLEDs), which were fabricated using a two-wavelength method. To optimize emission characteristics of white PHOLEDs, white PHOLEDs with co-doping and blue/co-doping emitting layer (EML) structures were fabricated using a host-dopant system. The total thickness of light-emitting layer was 25 nm and the dopant of blue and red was FIrpic and $Bt_2Ir(acac)$ in UGH3, respectively. In case of co-doping structure, applying micro lens array film showed efficiency improvement from the current efficiency 78.5 cd/A and power efficiency 40.4 lm/W to the current efficiency 131.1 cd/A and power efficiency 65 lm/W and blue / co-doping structure showed efficiency improvement from the current efficiency 43.8 cd/A and power efficiency 22 lm/W to the current efficiency 69 cd/A and power efficiency 32 lm/W.