• 한국세라믹학회지
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• 제50권1호
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• pp.75-81
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• 2013

We fabricated translucent opal glass to replace the polycarbonate diffuser in LED lighting systems in order to solve the durability problem. Batch materials of opal glass with a composition of calcium phosphate were created and melted at $1550^{\circ}C$, and the effect of opaqueness was identified by an addition of 1~7% calcium phosphate as an opacifier raw material. As a result, translucent opal glass was obtained by the melting of the mixed batch materials with a composition of more than 5% calcium phosphate glass at $1550^{\circ}C$ for 2 hrs, which had excellent optical properties for the diffuser of a LED lighting system with no dazzling from direct light by a high haze value exceeding 90% and a low parallel transmittance value of about 5%. For the thermal properties, the thermal expansion coefficient was found to be $5.6{\sim}5.9{\times}10^{-6}/^{\circ}C$ and the softening point was $874{\sim}884^{\circ}C$. In addition, good thermal properties such as good thermal shock resistance and feasibility for use with a general manufacturing process during the forming of glass tubes and bulbs were noted. Therefore, it is concluded that this translucent opal glass can be used as a glass diffuser material for LED lighting due to its high heat resistance and high durability as a replacement for a polycarbonate diffuser.

• 한국인터넷방송통신학회논문지
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• 제13권5호
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• pp.77-83
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• 2013

현재, 조명제어와 관리기술의 한계점은 유선으로 인한 시설비 과다, 운영의 어려움, 에너지낭비이다. 이를 해결하기 위해 조명기기에 무선네트워크 기능이 탑재된 스마트 조명 정보 시스템을 복합적으로 수행하기위한 통신 및 관리 소프트웨어가 필요하다. 본 논문에서는 LED조명의 전력량 모니터링을 통해 에너지 절감을 위한 기술을 개발하고, 이 기술을 융합하기 위해 전력 에너지 정보시스템 LEIS(Lighting Energy Information System)을 개발 했다. LEIS는 센서에 의해 지그비 메쉬망을 통해 수집된 전력 데이터를 모니터링하고 제어하는 시스템으로 조명의 사용에너지 정보를 사용자에게 시각화하여 보여준다. 이 시스템은 LEM(Lighting Energy Metering)의 정보를 바탕으로 한 전력정보 데이터베이스 및 LEIS 웹어플리케이션으로 구성되고 LEIS를 통해 에너지를 최적화하여 제어할 수 있는 시나리오 기능을 제공한다.

• Journal of Advanced Marine Engineering and Technology
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• 제36권1호
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• pp.64-71
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• 2012

An efficient cooling system is an essential part of the electronic packaging such as a high-luminance LED lighting. A special technology, Pulsating Heat Pipe (PHP), can be applied to improve cooling of a sealed, explosion-proof LED light fixture. In this paper, the characteristics of the pulsating heat pipes in the imposed thermal boundary conditions of LED lightings were experimentally investigated and a PHP device that works free of alignment angle was investigated for cooling of explosion-proof LED lights. Five working fluids of ethanol, FC-72, R-123, water, and acetone were chosen for comparison. The experimental pulsating heat pipe was made of copper tubes of internal diameter of 2.1 mm, 26 turns. A variable heat source of electric heater and an array of cooling fins were attached to the pulsating heat pipe. For the alignment of the heating part at bottom, an optimum charging ratio (liquid fluid volume to total volume) was about 50% for most of the fluids and water showed the highest heat transfer performance. For the alignment of the heating part on top, however, only R-123 worked in an un-looped construction. This unique advantage of R-123 is attributed to its high vapor pressure gradient. Applying these findings, a cooling device for an explosion-proof type of LED light rated 30 W was constructed and tested successfully.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2031-2039
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• 2015

In the LED lighting industry, the dimming function in the LED lamp is required by demands of many consumers. To drive this LED lighting, various types of power converters have been applied. Among them, an LLC resonant converter could be applied for high power LED lighting because of its high efficiency and high power density, etc. The function of power factor correction (PFC) might be added to it. In this paper, a dimmable single-stage asymmetrical LLC resonant converter is proposed. The proposed converter performs both input-current harmonics reduction and PFC using the discontinuous conduction mode (DCM). Also, the lower voltage stress across switching devices as well as the zero voltage switching (ZVS) in switching devices is realized by the proposed topology. It can reduce cost and has high efficiency of the driver. In addition, the regulation of the output power by variable switching frequency can vary the brightness of a light. In the proposed converter, one of the attractive advantages doesn’t need any extra control circuits for the dimming function. To verify the performance of the proposed converter, simulation and experimental results from a 300W prototype are provided.

• Journal of Advanced Marine Engineering and Technology
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• 제34권6호
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• pp.852-857
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• 2010

본 논문에서는 조명으로 사용되는 LED를 이용하여 실내 가시광 통신을 할 수 있는 시스템을 제안하고 있다. LED는 디지털 변조가 가능하므로 조명과 더불어 광무선 통신시스템으로 적용할 수 있다는 개념과 연구결과에 기인하여 기초연구를 수행하였다. LED는 고 휘도, 신뢰성, 저 전력 소비, 긴 수명의 장점을 가지므로 고 품질의 통신서비스를 제공하는 통신용 광원으로서도 적합하다. 본 연구에서는 오디오 전송을 위한 단방향 광무선 통신시스템과 텍스트 메시지를 전송하기 위한 양방향 통신시스템을 구현하여 통신 성능을 실험하였다. 이 실험결과는 실내 무선 환경을 지향하는 조명등의 내부회로로 설치될 수 있는 저가형 광통신 트랜시버의 구현이 가능함을 보여준다.

• Transactions on Electrical and Electronic Materials
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• 제18권1호
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• pp.35-41
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• 2017

This study looks at optimizinge light redistribution to improve the overall illuminance uniformity of commercial IRED modules. To obtain uniform illumination over a prescribed rectangular area, a freeform surface lens was evaluated using TracePro. The LED light overall illuminance uniformity regulated in KSC 7658 was verified using Relux software. Experimental test results showed 0.81 overall illuminance uniformity for rectangular light distribution of LED lights having a radiation angle of $80^{\circ}$. After fabricating prototype IRED lights based on these simulation results, illuminance performance was observed when used as actual IRED lighting with a nighttime CCTV system. Image observation photographs of the prototype $80^{\circ}$ rectangular IRED lights confirmed that object images can be seen clearly owing to high overall illuminance uniformity, and that dark regions of the CCTV screen were not shown.

• 한국광학회지
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• 제35권1호
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• pp.18-23
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• 2024

미술관 등 전시 공간에서의 조명은 바닥보다는 주로 전시물이 붙어 있는 벽면에 비춰져야 한다. 일반적으로 사용되는 LED 조명은 LED에 확산판이 결합된 형태로서 각도별 배광 분포가 일정한 램버시안 광원에 가까우며, 수직 입사가 이뤄지는 바닥면에 조명이 집중된다. 따라서 이러한 일반적 형태의 조명 방법은 벽면을 조명하기에는 적합하지 않으며, 벽면에 조명을 집중시키기 위해서는 각도별 배광 분포 중 각도가 큰 영역에서의 광량이 커지도록 해야 한다. 본 연구에서는 광원에서의 발산각을 180도로 확산시키기 위해 초광각 변환기를 사용하는 조명 광학계에 대해 논의하고자 한다.

• 한국정보기술학회 영문논문지
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• 제9권2호
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• pp.75-87
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• 2019

This paper presents a fully digital controlled power supply unit for the wireless controlled dimmable LED lighting system. The proposed power supply designed using a fly-back converter, which is directly controlled by a microprocessor. Although the proposed circuit does not sense the AC input current and has not AC input voltage feed-forward, it can achieve a high power factor. The proposed power supply directly regulates the output power for LED loads using the PWM and PFM control of the fly-back converter without additional regulator. For a wireless remote control function, the Zigbee modem is equipped in the proposed power supply. A prototype set-up has been built and tested. Through the experiment with a prototype set-up, the usefulness of the proposed power supply is verified.

• 디지털융복합연구
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• 제13권6호
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• pp.267-273
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• 2015

자칫 지루하게 느껴질 수 있는 책꽂이를 사용자의 행위에 의해 색상을 변화 시키며 즐길 수 있는 조명의 기능을 포함한 새로운 개념의 책꽂이로 디자인 하였다. 책꽂이의 조명을 탈착 가능하도록 디자인 하여 조명만을 따로 사용할 수도 있고, 조명 책꽂이는 모듈화 되어 있으며 메인 조명 책꽂이는 MCU(Micro Controller Unit), RGB LED와 컬러센서를 포함하고 있어 조명 책꽂이를 중심으로 아홉 개까지 네 방향으로 확장이 가능하다. 확장 가능한 다수의 조명 책꽂이는 MCU와 컬러센서를 내장하고 있지 않으며 단지 RGB LED만이 설치되어 있고 전원은 메인조명 책꽂이에서 공급 받을 수 있는 배선장치만을 가지고 있다. 메인 조명 책꽂이를 통해 전원과 색상 신호만을 전달 받아 서브 조명 책꽂이들은 조명의 색상을 변화 시킬 수 있다. 또한 사물인터넷의 기능을 포함한다. 본 연구는 이러한 센서를 이용해 책꽂이의 조명을 조절할 수 있는 모듈화된 디자인 제품의 제안이다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 정기총회 및 추계학술대회 논문집
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• pp.1486-1492
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• 2011

The Development of science and technology began with the use of fire. In addition to the invention of an artificial light, more time and activity areas were provided so that continuous technological development has continued. Also, artificial lights brought an improvement in productivity through the applications in various fields such as agriculture, livestock farming, fisheries, and so on. Especially, in the field of agriculture, LED has come to the front as an alternative for food security against extreme climatic change. Meanwhile, with great interest, many researches about the convergence of agricultural biotechnology and LED industry are ongoing over the world. This paper shows the correlation of the plants growth using the LED artificial lighting similar to sunlight, which is needed for photosynthesis, in subway station which has actually no natural lights. Also, it is expected that this paper will lay out the groundwork for improving an environmentally friendly image which gives a relief and an emotional effect to passengers by using nature friendly lighting.