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Optics Express

Optics Express

  • Editor: C. Martijn de Sterke
  • Vol. 17, Iss. 25 — Dec. 7, 2009
  • pp: 22311–22319

Evaluation of InGaN/GaN light-emitting diodes of circular geometry

X. H. Wang, W. Y. Fu, P. T. Lai, and H. W. Choi  »View Author Affiliations

Optics Express, Vol. 17, Issue 25, pp. 22311-22319 (2009)

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Blue GaN light emitting diodes (LEDs) in the shape of cuboids and circular disks have been fabricated by laser micromachining. The proposed circular geometry serves to enhance overall light extraction on a macro-scale and to improve uniformity of the emission pattern due to the rotational symmetry of the chip. Analysis of the chip shaping effect is carried out by ray-tracing simulations and further supported with mathematical modeling using ideal LED models, and subsequently verified with fabricated devices. In comparison, a 10% improvement in overall emission was observed for circular LEDs over the regular cuboids, consistent with simulations and calculations. The measured emission pattern from the circular LED confirms the axial symmetry of the emission beam.

© 2009 OSA

OCIS Codes
(220.0220) Optical design and fabrication : Optical design and fabrication
(230.3670) Optical devices : Light-emitting diodes

ToC Category:
Optical Devices

Original Manuscript: August 24, 2009
Revised Manuscript: November 6, 2009
Manuscript Accepted: November 16, 2009
Published: November 23, 2009

X. H. Wang, W. Y. Fu, P. T. Lai, and H. W. Choi, "Evaluation of InGaN/GaN light-emitting diodes of circular geometry," Opt. Express 17, 22311-22319 (2009)

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  1. D. S. Han, J. Y. Kim, S. I. Na, S. H. Kim, K. D. Lee, B. Kim, and S. J. Park, “Improvement of light extraction efficiency of flip-chip light-emitting diode by texturing the bottom side-surface of sapphire substrate,” IEEE Photon. Technol. Lett. 18(13), 1406–1408 (2006). [CrossRef]
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