• Journal of the Korean Institute of Telematics and Electronics A
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• v.32A no.9
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• pp.128-134
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• 1995

A fiber-optic temperature sensor utilizing an optical absorption device (InP) was fabricated. The spectrum of transmitted light through an InP device was obtained at the three temperatures(249 K, 369 K). A stabilized LED(light emmiting diode) driver, photoreceiver, and signal proocessing electronics were designed. An intensity referencing technique was adopted in order to minimize the fluctuation of output signal due to external pertubation of the transmitting optical fiber. The optical absorption edge of the InP device moves to longer wavelength at a rate of 0.42 nm / K, and energy gap of InP is 1.35 eV at room temperature. From these results, it is concluded that the InP device has temperature dynamic range of 300 K with LED of center wavelength of 940nm and spectral width of 50nm. The designed fiber-optic temperature sensor system showed good linearity within the temperature range from -30$^{\circ}C$ to + 150$^{\circ}C$.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.846-849
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• 2009

In this study, we manufactured polymer-LED using light emitting copolymer as the active layer. After cathode layer deposition, we did post-annealing at $150^{\circ}C$ during 10 min in $N_2$ glove box. Then, we confirmed that the efficiency of the device was significantly enhanced by post annealing process. Its value was increased from 0.18(cd/A) to 1.32(cd/A), approximately 7 times. This phenomenon is a result of improved stability between polymer and metal cathode for injection of electrons as the contact density increases.

• Smart Media Journal
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• v.8 no.3
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• pp.47-52
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• 2019

In this paper, we designed HW / SW interfaces for processing the signals of capacitive sensors like Electric Potential Sensor (EPS) to detect the surrounding electric field disturbance as feature signals in motion recognition systems. We implemented a smart light control system with those interfaces. In the system, the on/off switch and brightness adjustment are controlled by hand gestures using the designed and fabricated interface circuits. PWM (Pulse Width Modulation) signals of the controller with a driver IC are used to drive the LED and to control the brightness and on/off operation. Using the hand-gesture signals obtained through EPS sensors and the interface HW/SW, we can not only construct a gesture instructing system but also accomplish the faster recognition speed by developing dedicated interface hardware including control circuitry. Finally, using the proposed hand-gesture recognition and signal processing methods, the light control module was also designed and implemented. The experimental result shows that the smart light control system can control the LED module properly by accurate motion detection and gesture classification.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.938-940
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• 2012

전세계적으로 친환경, 에너지 절약과 맞물려 LED조명에 대한 관심이 증대되고 있다. 특히 우리나라는 삼면이 바다와 인접해 해안 항만 환경에 대한 관심이 높고, 해안산책로, 공원 등이 늘어나면서 LED 보안등에 대한 수요가 늘고 있는 추세이다. LED보안등의 수요가 늘어나면서 보안등의 주목적인 범죄예방에 대비하면서 에너지를 절감할 수 있는 시스템에 대한 관심이 증대되고 있다. 최근의 조명제어 시스템은 단순히 보행자 유무만을 인식하여 조명의 밝기를 제어하는 시스템이 대다수이며, 비, 바람, 안개, 해무 등의 실시간 변화가 잦은 해안환경에 대한 고려는 부족하다. 따라서, 본 논문에서는 보행자 유무와 비, 안개, 해무 등의 환경적 정보를 융합하여 보안등의 밝기를 통합 제어할 수 있는 스마트 제어 시스템을 설계하고자 한다.

• Journal of Sensor Science and Technology
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• v.27 no.3
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• pp.175-181
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• 2018

In this paper, we introduce a new dimming control method in a visible light communication (VLC) system wherein byteinversion is adopted for flicker-free transmission. In the VLC transmitter, the original and the inverted data were sent sequentially and the remnant time in one period was used for the dimming control of the LED light. In the VLC receiver, only the original data was recovered using the gating signal whose width was the same as the length of the original data. In our experiments, the dimming control ranges were measured to be 22%-53%, 11%-76%, and 5%-88% of the CW LED light when the data rates were 9.6, 19.2, and 38.4 kbps, respectively. In this system, we used a 240-Hz sync pulse whose period was 4.16 ms, which was shorter than the maximum flickering time period of 5 ms that is generally considered to be safe. This configuration is very simple and useful in constructing indoor wireless sensor networks using the flicker-free LED lamps with dimming control capability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2017.05a
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• pp.81-83
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• 2017

우리 삶의 다양한 분야에서 ICT 기술을 적용하여 편의성과 활용성이 증대되고 있다. 본 논문에서는 최근 다양한 응용에 활용되고 있는 아두이노(Arduino)를 기반으로 사람의 움직임에 따라 이용할 수 있는 Accelerometer와 FSR 센서를 사용하여 RGB LED Strip을 제어하고 여러가지 색상을 다양한 패턴으로 나타나게 하며, 해당 움직임을 모니터링할 수 있는 시스템을 제안한다. 이는 사람의 움직임 또는 동작을 취하는 다양한 신체부위에 적용해 볼 수 있다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.855-856
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• 2011

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.11a
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• pp.119-124
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• 2007

24" LCD Monitor용 LED BLU를 개발하기 위하여 1.5W R,G,G,B가 하나의 PKG에 들어있는 LED를 이용하여 Direct type의 Back Light Unit을 개발하였다. 방열 및 휘도 균일도를 고려하여 LED part를 설계, 개발 하였고 LED를 pulse로 구동하기 위하여 Switching circuit이 포함되는 구동회로 부분을 설계, 개발하였다. 또한 Color Sensor와 ICM (Integrated Color Management) IC를 사용하여 Color를 Control하는 제어회로 부분도 개발을 하였다. 제어회로 부분을 개발하기 위하여 MicroController를 사용하였으며 ICM IC와의 통신을 위한 부분도 개발하였다. 이러한 구성을 개발하여 시제품을 직접 제작하였다. 평가를 위하여 성능시험을 실시하였고 광학적인 평가도 시행하였다. 제작된 시제품은 $L558{\times}W359{\times}H30$으로 하였다. 휘도는 목표휘도를 이루었으며 균일도는 85% 이상이 되었다.

• The Journal of the Korea institute of electronic communication sciences
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• v.9 no.4
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• pp.499-508
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• 2014

In this paper, we implemented a LED sensitivity illumination system, being driven in response to changes in the biological signals of GSR and PPG signal. After measuring biological signals of a human body from GSR and PPG sensor modules, MCU decided the state of relaxation or arousal of the subject, being based on the wake relaxation identifying map proposed in this paper. A developed LED sensitivity illumination system makes the subject to reach a normal state by giving a change of the LED illumination color, corresponding to a state of the subject.

• Journal of Electrical Engineering and Technology
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• v.12 no.4
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• pp.1593-1599
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• 2017

This paper presents a multi-channel light-emitting diode (LED) driver IC with a current-mode current regulator. The proposed current regulator replaces resistors for current sensing with a sequentially controlled single current sensor and a single regulation loop for sensing and regulating all LED channel currents. This minimizes the current mismatch among the LED channels and increases voltage headroom or, equivalently, power efficiency. The proposed LED driver IC was fabricated in a $0.35-{\mu}m$ BCD 60-V high voltage process, and the chip area is $1.06mm^2$. The measured maximum power efficiency is 93.4 % from a 12-V input, and the inter-channel current error is smaller than as low as ${\pm}1.3%$ in overall operating region.