• 산업경영시스템학회지
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• 제33권4호
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• pp.79-84
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• 2010

In recent years, conventional streetlight is replaced by LED streetlight to reduce power consumption dramatically and to maximize lighting effects. However the characteristic of power LED itself driven by high current to increase the illumination, we need to develop effective heat release device. This study suggests new concept of heat dissipation device using PCM (Phase Change Material) and shows an experiment results to investigate thermal effects of PCM.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.335-337
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• 2008

In this paper, an X-Y channel dimming light emitting diode (LED) backlight with temperature compensation for in LCD TVs is proposed. It shows local dimming effects such as reduced power consumption and high dynamic contrast ratio even with much less number of LED drivers than that of the conventional two-dimensional local dimming method. Moreover, the image distortion caused by temperature variation of LED block can be effectively compensated. The validity of the proposed dimming method is verified by simulation and experimental results based on a RGB-LED backlight of a 32-inch LCD TV.

• 전기학회논문지P
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• 제65권2호
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• pp.142-150
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• 2016

This paper developed new manufacture process technology of slim type flexible flat lighting product used lower power white LED. Flexible flat lighting is applied to letter sign lighting, traffic lighting, interior wall lighting, flat lighting, aquarium back lighting, wreath light etc. Main manufacture process technology were developed drawing software for electronics circuit, inkjet electronic circuit pattern and inkjet white ink coating. For pattern printing it was utilized for piezoelectonic inkjet head printing technology. Also high vacuum pressure laminating technology was waterproofing for LED flat lighting protection. Hence, form process technology we were manufactured for flexible flat lighting product of the power 12 W, input voltage 48 V and plane size $480{\times}480mm$. It acquired a these validity from experiment results.

• 전기전자학회논문지
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• 제23권2호
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• pp.571-579
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• 2019

가시광통신은 조명과 통신을 동시에 수행하므로, 데이터 전송과정에서 광전력의 변동으로 인하여 발생하는 플리커를 방지함과 동시에 조명제어 기능을 갖추는 것이 중요하다. 본 논문에서는 플리커를 방지하고 조명제어를 위하여 맨체스터코드를 사용하였다. 송신부에서는 맨체스터코드의 듀티율을 사용하여 LED의 조명을 제어하였고, 수신부에서는 RC-고역통과필터의 가장자리 스파이크 신호를 사용하여 인접된 잡음광을 차단하고 맨체스터코드를 복구하였다. 실험에서 LED 빛은 플리커가 없는 상태를 유지하였고, 맨체스터코드의 듀티율을 변경함으로써 평균 광전력을 CW LED 광의 약 8~68 % 의 범위에서 제어하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 C
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• pp.1669-1670
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• 2006

LED have many problem as narrow light view angle, high price, drift phenomenon of color coordinate, high heating problem for lower power, lower weight and small size. But, with the development of blue LEDs and the improvement of LED brightness, color variation are becoming more and more popular as lighting and application devices in this page, 1 used the Light Tools which was a simulation program in order to recognize optical a few characteristic of LEDs arrangement along reflector matrial and designed LED Arranged 5 phi LED in 5mm interval In the square that was $10{\times}10$ And designs a reflection board on pcb, structural design of PCB changed as five type. - Aluminum, Gold. Chromium, Nickel, Copper.

• 조명전기설비학회논문지
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• 제30권3호
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• pp.94-105
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• 2016

The objective of the work was to evaluate the impact of lighting energy to cooling and heating consumption in medium scale office building, when currently installed fluorescent lights were replaced with various LED lighting fixtures. This evaluation comes from an integrated approach combining the proper indoor lighting environment and the thermal aspects of cooling & heating consumption in office building. These simulations were performed by coupling an appropriate luminaire analysis for energy consumption and a dynamic thermal simulation software (TRNSYS). To analyze comparative study of effects on the heating, cooling loads, and energy consumption of an LED lamp application, 2 types of LED lamp with low light power watt(LPW) 24W and high LPW 7.5W and a fluorescent lights(FL) with 37W are used respectively. Integrated building energy consumption decreased up to 3.2% when fluorescent lamps were replaced with LEDs. Thus, the high LPW of LED(7.5W) replaced with the same number of FL shows an effective energy saving and cost- effective luminary.

• 한국신뢰성학회지:신뢰성응용연구
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• 제10권2호
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• pp.137-148
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• 2010

This study deals with the accelerated life test of high power phosphor converted white Light Emitting Diodes (High power LEDs). Samples were aged at $110^{\circ}C$/85% RH and $130^{\circ}C$/85% RH up to 900 hours under non-biased condition. The stress induced a luminous flux decay on LEDs in all the conditions. Aged devices exhibited modification of package silicon color from white to yellowish brown. The instability of the package contributes to the overall degradation of optical lens and structural degradations such as generating bubbles. The degradation mechanisms of lumen decay and reduction of spectrum intensity were ascribed to hygro-mechanical stress which results in package instabilities.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.159-159
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• 2010

We conducted bum-in test by current stress to evaluate acceleration reliability characteristics about p-resistivity influence of GaN-based light-emitting diodes. The LEDs used in this study are the polarization field-induced LED(PF-LED) having low p-resistivity and the highly resistive LED(HR-LED) having high p-resistivity. The result of high stress experiment shows that current crowding phenomenon is occurred from the center of between p-bonding pad and n-bonding pad to either electrodes. In addition, series resistance and optical power decrease dramatically. These results means that the resistance of between p-bonding pad and p-GaN affect reliability. That's why we need to consider the ohmic contact of p-bonding pad when design the high efficiency and high reliability LEDs.

• 한국전자통신학회논문지
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• 제13권1호
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• pp.85-92
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• 2018

본 논문에서는 $-40^{\circ}C$에서 동작하는 150W급 LED조명용 전원공급장치(SMPS) 회로를 설계하였다. SMPS의 특성 해석을 위해서 150W급 LED 조명 구동 정전류 회로를 설계하고 시제품의 제작 및 성능을 측정하였다. 150W급 LED조명용 SMPS 회로의 동작온도범위는 $-40{\sim}70^{\circ}C$이며, SMPS 예측 수명은 24시간 기준으로 1.29~2.25년으로 예측되었다. 초가속수명시험 및 EMI 전도 시험을 통해 이상이 없음을 확인하였다.

• 한국태양에너지학회 논문집
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• 제31권2호
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• pp.113-119
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• 2011

LED lighting has received much attention in recent years due to its high energy efficiency and environmental friendliness. As the color of light can be obtained by adjusting the light intensity of LEDs, the quality of visual environment can be improved. The aims of this study are to develop a wavelength adjustable LED lighting system and to examine its lighting performances. The LED lighting system and experimental cell for assessment of the lighting performance were constructed. This LED lighting system is able to materialize the various spectral power distribution and color temperature of light through the control of the four dimmers. Up to $432^4$ kinds of light combinations are possible. The range of illuminance on workplane were measured as 7~1,831 ㏓. Improvement of psychological and physical functions for occupants can be expected according to control of lighting performances.