• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.4
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• pp.32-37
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• 2014

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3517-3523
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• 2010

Single exposure dual X-ray imaging can be used to separate soft and dense-material images for medical and industrial applications. This study keep focusing baggage inspection system(BIS) specifically. New detector modules for single exposure dual X-ray imaging are consisted of low energy detector (LED) and high energy detector (HED). First, the optimized thickness of copper filter coupled HED to separate low energy and high energy was simulated by the given X-ray energy (140 kVp, 1 mA) using Monte Carlo simulation codes, MCNPX. So as a result of simulation, the copper filter thickness is 0.7 mm. For the design of PIN photodiode, ATLAS device simulation tool was used. 16 channels PIN photodiode of 1.5 mm ${\times}$ 3.2 mm for Dual X-ray imaging detector was fabricated in the process of ETRI. And its dark current and quantum efficiency, terminal capacitance were measured. It was proven that the Lanex Fast B coupled HED were a sufficient candidate to replace the CsI(Tl) commerced in dual X-ray system, since these give a strong signal, overcoming system noise. Finally dual X-ray image was acquired through correction of the LED X-ray Image and the HED X-ray Image.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.485-490
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• 2012

In this paper, driver circuit of LED lights for ships is designed and implemented to replace conventional lights with filament which have short life time due to vibration of ships. The driver of LED module is switching circuit without transformer to reduce volume and cost. As switch circuit controls input 220 VAC with PWM, LED module is reliably driven. Power factor is improved by using valley-fill PFC compensation circuit which is handled to pulse current of switching circuit. Serial-parallel LED circuit is applied to reduce change period of lights of long-term navigation ships. Array of serial-parallel can operate even if some of LEDs is damaged. It is suitable for ships that power consumption and power factor of lights including developed drive circuit have 39Watt and 0.925 respectively.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.20 no.4
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• pp.452-457
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• 2011

The internal temperature of an operating room had to keep within $20^{\circ}C$. However, the doctor who is wearing operating gown and mask caused to rise temperature because of the thermal occurrence of dental LED light source. At first, the surgery environment is getting worse. And then last, it would increase bleeding rate by the expansion of patient's exposured blood vessel. A surgical operator can distribute the patient's tissue through such surgery environment, exactly. It can do accurate surgery. So, it gave to effect that surgical operator's eye condition is getting better and it could keep a mutual assistance system. For this research, we develop the LED dental light source module of high color rendition. It performed simulation for replacing established the method of Halogen lamp and Plazma lamp of light source. We analyzed intensity of illumination and the change of viability by changing the height of light source module.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.480-481
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• 2012

LED (Light Emitting Diode)는 친환경적이며 고수명 등의 여러 장점을 가지고 있어서 액정디스플레이의 광원으로 널리 사용되고 있다. 그러나 LED 제품을 제조하기 위해서는 칩, 패키지, 모듈, 시스템으로 구성된 4단계의 복잡한 제조공정을 거쳐야 하므로 가격이 높은 단점이 있다. 이를 개선하기 위해서 패키지, 모듈, 시스템의 3단계의 공정을 하나로 통합한 hybrid LED package(HLP) 개념이 제시되었다. HLP는 LED chip을 PCB에 직접 실장한 뒤 초정밀 가공 및 성형 기술을 활용하여 일체형 광학패턴을 인가함으로써 공정을 단순화하면서도 광효율을 향상시킬 수 있다. 이에 본 연구에서는 다구찌 실험계획법을 사용하여 디스플레이에서 중요시되는 휘도를 높일 수 있는 일체형광학패턴 형상 최적화를 실시하였으며, 최적화된 일체형 광학패턴을 제조하기 위한 초정밀 가공 및 성형기술을 개발하였다. 최적화 결과 높이 25um, 꼭지각 90도의 음각형태의 사각피라미드 패턴이 최적형상으로 결정되었으며, 패턴이 없을 때와 비교하여 휘도가 약 32.3% 높아지는 것으로 나타났다. 이러한 일체형 광학패턴을 제품으로 구현하기 위하여 초정밀 절삭기술을 활용하여 마스터 금형을 제작하였다. 최종적으로 사출성형을 통해 일체형 광학패턴을 제작하게 되는데 이때 사출기 내부 공기흐름 및 진공도를 최적화함으로써 패턴 내부에 불필요한 기포가 발생하지 않도록 하는데 성공하였다. 이를 통해 생산성이 높은 사출성형으로 HLP 제품을 양산할 수 있는 가능성을 확인하였고, 추후에는 실제 제품을 제작하는 연구를 수행할 예정이다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.21-23
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• 2009

The paper is to evaluate for reliability of LED Modules for Lighting by ALTs(Accelerated Life Tests). The recently, some of KS were established by law of LED Modules for Lighting(KS C 7651, KS C 7652 and KS C 7653), but reliability assessment methods of LED Modules for Lighting were not established. Therefore, the paper aided companies to test methods for accelerated life testing by themselves.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.99-106
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• 2016

Wearable display market is a consistently growing field to handle a smart device with ease. Wearable display is an efficient device that can show the information to the user. In this paper, propose the scheme of a wearable display using LED and implement it including controlling remotely with BLE. Traditional outdoor LED display requires the dedicated controller and its software. Therefore, to control those LED display, it should implement a driver and its own way of communication. The proposed method is to ensure the independence and extensibility by separating driver module and communication module for controlling LED display. In addition, by adopting a short-range communication with Bluetooth 4.0 and a LED driver with low-power technology, it can be showed to control system configuration and display with a smart device.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.37C no.11
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• pp.1020-1026
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• 2012

In this paper, we proposed a RTOS-based lighting control system to improve energy efficiency. This proposed system, real time process was designed to the specified division of the LED streetlight control module for the RTOS-based lighting control into three different tasks. The first task transmits LED lighting signal by measuring illuminance, and the second task transmits motion detecting signal using motion detector. In the third task, lighting control to LED was designed through passed control signal from other tasks The execution status was examined ports that are directly to the ATmega128 MCU for the verification of the system, and illuminance distribution and operating conditions were verified through LED street field test. The proposed RTOS-based lighting control system has brought improving system performance and also facilitate an addition of other functions, and it was possible to optimize energy saving by intelligent lighting pattern control.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.12
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• pp.10-22
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• 2009

This paper presents an LED lighting system with an LED color control algorithm that can independently change its color temperature and illuminance. To show the validity of the proposed algorithm, it is proven that its solution always exists. The proposed algorithm was applied to the control of an LED module that is composed of red, green, blue, and white (RGBW) LEDs. Its color temperature variation ranged from 3,500~7,500[$^{\circ}K$], and its illuminance ranges from 500~1,500[lux]. Within these range, the color temperature and illuminance deviations are as low as $\pm0.8$[%] when the junction temperature of LEDs are maintained at 40[$^{\circ}C$]. In the range of 30~70[$^{\circ}C$], the measured illuminance and color temperature deviations are as low as 2.1[%] and 3.6[%], and the compensated ones are as low as 1[%] and 0.49[%], when the desired illuminance and color temperature are 1,000[lux] and 6,500[$^{\circ}K$], respectively.nyang.ac.kr).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.786-791
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• 2021

In this paper, in order to minimize limitations such as signal interference and positioning errors in existing indoor positioning systems, a smart LED-based positioning system for excellent line-of-sight radio environments and precise location tracking is proposed to improve accuracy. An IEEE 802.4 Zigbee module is mounted on the SMPS board of a smart LED; RSSI and LQI signals are received from a moving tag, and the system is configured to transmit the measured data to the positioning server through a gateway. For the experiment, the necessary hardware, such as the gateway and the smart LED module, were separately designed, and the experiment was conducted after configuring the system in an external field office. The positioning error was within 70cm as a result of performing complex calculations in the positioning server after transmitting a vector value of the moving object obtained from the direction sensor, together with a signal from the moving object received by the smart LED. The result is a significantly improved positioning error, compared to an existing short-range wireless communications-based system, and shows the level at which commercial products can be implemented.