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루미나리에(Luminarie)용 고출력 LED패키지 배광분포 모델링 및 광학적 특성 분석
조재문,김병일,곽준섭,윤동주,유진열,Cho, Jae-Moon,Kim, Byung-Il,Kwak, Joon-Seop,Yoon, Dong-Joo,Yu, Jin-Yeul 한국광학회 2007 한국광학회지 Vol.18 No.4
기존 필라멘트 방식의 루미나리에용 조명의 단점을 극복하기 위해 필라멘트를 LED로 바꾸기 위한 연구가 활발하게 진행 중이다. 본 연구는 루미나리에용에 적합한 LED패키지 구조를 만들기 위해 ray tracing simulator를 이용해 다양한 구조를 모델링하고 시뮬레이션을 통해 각 구조에서의 배광분포를 측정하였다. 시뮬레이션 결과, LED 패키지의 내부 반사경의 각을 증가시킬수록 배광분포가 두 개의 피크로 갈라지면서 피크간의 각이 점점 커졌다. 또한 외부 반사경 각이 증가함에 따라 양쪽 피크간의 각이 점점 줄어들다가 $50^{\circ}$를 기준으로 다시 증가하였다. 이러한 결과는 LED에서 발생한 빛이 두 개의 반사경에 의하여 반사되는 각도가 달라짐에 의하여 발생함을 알 수 있었다. Ray tracing simulator를 이용하여 구한 LED 패키지 구조의 조건을 적용하여 루미나리에용 LED패키지를 제작하였고 배광분포 측정기를 이용해 광 특성을 측정하였으며 시뮬레이션의 결과와 유사한 특성을 얻었다. Today's research has been focused on changing the light source from filament to LED for luminarie illumination to overcome the shortcoming of a filament. The purpose of this research is to make an appropriate high power LED package structure for luminarie. We simulated radiation patterns of the various structures by the ray tracing simulator (Light Tools), and also analyzed the radiation patterns using an LED test system (OL770). As we increased an inner reflector angle, the radiation pattern split into two peaks and the angle between two peaks became larger. In addition, when we increased an outer reflector angle, the angle between side peaks gradually decreased, while it increased again when the angle reach $50^{\circ}$. These results could be understood from the ray tracing of the light reflected from two reflectors. We made the high power LED package for luminarie on the condition of the optimized structure which was made by ray tracing simulation results, and we measured the radiation patterns by using an LED test system, and these results were well matched to the simulation results.
백유진 ( Yu Jin Back ),김언수 ( Eon Soo Kim ),남대일 ( Dae Il Nam ) 한국중소기업학회 2013 기업가정신과 벤처연구 Vol.16 No.2
Will more social relations always bring better performance for entrepreneurial firms? Using a sample of all firms which went through an IPO during 2001-2004 in the U.S., we examine the relationship between social relations of entrepreneurial firms and their performance. Prior research has suggested that having relationships at the early stage of organizational life provides many advantages to entrepreneurial firms. Entrepreneurial firms facing severe uncertainty can gain benefits from social relations, because relations can provide access to various resources. To a certain point, we accept this well-known thesis. However, we argue that too many relations may have detrimental consequences to firms` success. We introduce possible negative mechanisms and test the effect of immoderate level of social relations on the entrepreneurial firms` performance. We expect that social relations of entrepreneurial firms will have an inverted U-gshaped relationship with performance. We specify social relations of three important groups (founder, TMT, and BOD) in entrepreneurial firms and examine their impact on the IPO performance. As a result, social relations of TMT and BOD have an inverted U-shaped relationship with IPO performance as expected. However, founder interlock has a negative impact on IPO performance. Finally, implications and limitations are discussed.