Korean Journal of Optics and Photonics (한국광학회지)

Optical Society of Korea (한국광학회)
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Variation of Illumination Performance with Source Size and Tolerance Characteristics of Freeform LED Lenses

LED 광원 크기에 따른 자유 형상 렌즈의 조명 성능 변화와 공차 특성

  • Yang, Jae-Suk (School of Information and Communication Engineering, INHA University) ;
  • Kim, Dae-Chan (LED-Smart Technology Advanced Research center INHA University) ;
  • O, Beom-Hoan (School of Information and Communication Engineering, INHA University) ;
  • Park, Se-Geun (School of Information and Communication Engineering, INHA University) ;
  • You, Il Hyun (SEMYUNG University) ;
  • Lee, Seung Gol (School of Information and Communication Engineering, INHA University)
  • 양재석 (인하대학교 정보통신공학과) ;
  • 김대찬 (인하대학교 정보통신공학과 고성능 LED조명모듈 핵심기술 연구센터(LED-STAR)) ;
  • 오범환 (인하대학교 정보통신공학과) ;
  • 박세근 (인하대학교 정보통신공학과) ;
  • 유일현 (세명대학교 정보통신학부) ;
  • 이승걸 (인하대학교 정보통신공학과)
  • Received : 2012.11.15
  • Accepted : 2012.12.21
  • Published : 2013.02.25
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Abstract

In this paper, the illumination performances of three freeform lenses optimally designed for a point source were investigated for several LEDs with different source sizes, and also the tolerance characteristics of the lenses were analyzed. For comparison, two lenses with different sizes were designed with a divergent illumination model, and the last one was done with an overlapped illumination model. As the LED source size increased, the illuminance uniformity decreased more strongly, and the influence of a source misalignment on illumination performance became insignificant. However, the variation of LED radiation characteristics had strong effect on the illumination performance, irrespective of LED source size. Even though the lens based on a divergent illumination model showed superior performance compared to the lens based on an overlapped illumination model, the latter was less sensitive to the variation of LED radiation characteristics.

본 논문에서는 점광원을 기준으로 설계된 자유 형상 렌즈(freeform lens)의 조명 성능과 LED 광원 크기와의 관계 및 공차 특성을 살펴보았다. 비교를 위해 발산 조명 모델(divergent illumination model)을 적용한 두 가지 렌즈와 중첩 조명 모델(overlapped illumination model)을 적용한 한가지 렌즈를 설계하였다. LED 광원이 커짐에 따라 평균 조도에 비해 조도 균일도가 상대적으로 크게 감소하였으며, 정렬 오차에 의한 성능 저하는 거의 발생하지 않았다. 하지만 LED 광원의 방출 특성 변화는 LED 광원 크기에 관계없이 조명 성능에 영향을 미치는 것으로 확인하였다. 발산 조명 모델로 설계된 렌즈가 전반적으로 우수한 성능을 보였지만, LED 방출 특성 변화에 대해서는 중첩 조명 모델로 설계된 렌즈의 성능이 상대적으로 적게 변화함을 알 수 있었다.

Keywords

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