• 전력전자학회논문지
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• 제18권2호
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• pp.117-122
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• 2013

The distributed power conversion LED driver circuit using parasitic inductance is proposed in this paper. while the conventional LED driver circuit is composed of the large size devices and heatsinks, the proposed circuit can be realized with the small sized no heatsink based. since the processing power can be effectively distributed. Also by using the wire parasitic inductance of the LED string, the proposed circuit can be implemented without external magnetic device. As a result, the proposed circuit which features the small size and volume con be realized even without LED driver module(LDM) board. since, all the device can be attached to the existing LED array Module(LAM) board. Therefore, it features that cost savings and volume reduction of circuit. To confirm the validity of the proposed circuit, theoretical analysis and experimental results from a distributed power conversion LED driver circuit prototype are presented.

• 센서학회지
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• 제24권4호
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• pp.232-238
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• 2015

In this paper, we introduce a passive transponder in which an LED is used for both a light transmitter and a receiver, and a solar cell is used for supplying power to the all devices in the transponder. The LED in the transponder operates as a photodetector in the receiving mode, and acts as a light source in the transmitting mode. The current responsivity of the LED detector was measured to be in the order of $10^{-4}A/W$, and the receiving bandwidth with a load resistance of $10k{\Omega}$ was about 10 to 30 kHz. Using the LED for an optical transceiver in a VLID transponder, the detection range was about 70 cm when the transponder was illuminated by the visible light from a $3{\times}3$ LED array in a reader.

• 조명전기설비학회논문지
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• 제26권4호
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• pp.14-21
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• 2012

This paper study a method of modeling and simulation of LED driver circuit for a design optimization. Simplified LED modeling is introduced and a driver IC, HV9910, is modeled by implementing the major function blocks. Circuit of buck type converter is constructed for simulation. Simulation includes not only the internal function of IC but also the various performance results such as LED array current control and dimming. Experiment results are also shown to prove the verification of its usage. This results show that the simulation approach is valid for a circuit optimization and a reduction of development time.

• Transactions on Electrical and Electronic Materials
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• 제9권3호
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• pp.110-115
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• 2008

In this paper, we have designated a 42-inch RGB LED BLU, 80 % above illuminance. A desirable brightness performance was attained, by doing anti-parallel configuration, a fitting of LED's strip distance and a height of the top of LED to the back of the LCD. We get the 85.81 % of the brightness uniformity which has 12.8 mm away from LED's top and LCD's back and 51.41 mm of the same spacing between LED's strip in simulation and 82.24 % in experiment.

• 한국광학회:학술대회논문집
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• 한국광학회 2006년도 동계학술발표회 논문집
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• pp.371-372
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• 2006

A 10Mbps optical wireless link using LED array has been demonstrated. The modulation bandwidth of the LED has been measured, and the transmission test according to modulation frequency has been also carried out. The good communication performance has been obtained at about 30cm distance at 10Mbps data rate.

• 융복합기술연구소 논문집
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• 제3권1호
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• pp.37-40
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• 2013

Plant factory industry as a new agriculture is in the spotlight. In this paper, we experimented plant factory applied photovoltaic system and LED lighting. For growing the plant, red, blue and white LED were placed into 1:4:3. Electric power generated by the photovoltaic system was supplied on DC power supply instead of AC. The designed and experimented power generation amount per day of photovoltaic system were 2,860 Wh and 2,272 Wh respectively. Plant has not been grown at the dead space of LED lighting so it is required to array LED lighting.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.395-395
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• 2013

GaN는 LED, 태양전지, 그리고 전자소자 등에 쓰이는 물질로, 관련 연구가 활발히 진행되고 있으며, 이와 더불어 top-down방식을 활용한 소자제작 방법 또한 발달되고 있다. 하지만, 일반적으로 LED 제작에 사용되는 c-plane GaN의 경우, c축 방향으로 발생하는 분극의 영향을 받게되며, 분극은 LED내 양자우물의 밴드를 기울게 하여 전자와 홀의 재결합률을 감소시켜 낮은 내부양자효율을 야기한다. 이러한 문제를 해결하기 위해 여러 가지 방법들이 제시되었으며, 그 중에서도 a면, 혹은 m면과 같은 nonpolar면을 사용하는 GaN LED가 주목받고 있다. 본 연구에서는, top-down방식을 통해 약 $2{\mu}m$ 크기의 diameter를 갖는 micro-sized column LED를 구현하였으며, 식각 후 드러나는 semipolar면을 wet treatment를 통해 제거하여 nonpolar면을 드러나게 하였으며, 이 면에 Ni/Au를 contact하여, 전기적, 광학적 특성을 논하였다. Fig. 1은 I-V 특성 그래프이며, Fig. 2는 EL측정 결과(광학적 특성)이다.

• 마이크로전자및패키징학회지
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• 제24권2호
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• pp.55-59
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• 2017

본 논문은 마이크로 BGA(Ball Grid Array)의 3차원 형상 검사를 위한 광학적 방법에 관한 것으로, 특히, LED를 공간적으로 배치한 광원과 경면반사특성을 이용하였다. 이를 위해 비전시스템을 구성하여 BGA의 반사영상을 취득한 후, 영상처리를 통하여 반사된 LED 점광원의 위치를 추출하여 형상검사에 이용하였다. 또한, 영상에 포함된 복수개의 BGA에 대한 상대적 위치의 통계치를 이용하여 BGA 3차원 형상의 결함을 판단하는 방법을 제안하였고, 실험을 통하여 제안된 방법의 효용성을 보였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.375-376
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• 2007

In this work, we have simulated a 42-inch LED BLU which was based on 300 RGB LEDs. We have done an adjustment of LEDs' strip distance and a height of the top of the LED to the back of the LCD to get white color uniformity. So, we have changed simultaneously the distance between the top of the LEDs and the back of the LCD. Moreover, we set a fixed position for the horizontal of LED's pitch. And then, we have experimented and compared to our simulation data.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2004년도 전력전자학술대회 논문집(2)
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• pp.851-854
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• 2004

This paper studies Optical Fiber(OF) - LED illuminated display board system for energy saving. The OF-LED illuminated display board system has PV modules, batteries, and charge & discharge system, and dynamic full color display controller. Both maximum power point tracker (MPPT) and constant current & constant current controls (CCVC) are used In govern the charging system. It can be improve the charging efficiency of battery. The objective of this thesis paper is to build advertisement lighting system with OF-LED in to charge a 12-volts lead acid battery by using a field wired PV array. We saved the maintenance cost and developed of advertisement effectiveness. To verify the proposed OF-LED illuminated display board system for energy saving, the detail simulation and experiment results indicate that operating characteristics are verified by experiment with a laboratory prototype in this paper.