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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 48, Iss. 6 — Feb. 20, 2009
  • pp: 1190–1197

Far-field condition for light-emitting diode arrays

Ivan Moreno, Ching-Cherng Sun, and Rumen Ivanov  »View Author Affiliations

Applied Optics, Vol. 48, Issue 6, pp. 1190-1197 (2009)

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In practice, any cluster of light-emitting diodes (LEDs) can be modeled or measured as a directional point source if the detector is far enough away from the cluster. We propose a far-zone condition for measuring or modeling propagation of light from an LED array. An equation gives the far-field distance as a function of the LED radiation pattern, array geometry, and number of LEDs. The far field is shorter for high packaging density clusters, and the far field considerably increases with increasing beam directionality of LEDs. In contrast with the classical rule of thumb (5 times the source size), the near zone of an array with highly directional LEDs can extend to more than 60 times the array size. We also analyze the effect of introducing random variations of light flux among LEDs of the array, which shows that far-field variability is low in high packaging density arrays.

© 2009 Optical Society of America

OCIS Codes
(120.4800) Instrumentation, measurement, and metrology : Optical standards and testing
(120.5240) Instrumentation, measurement, and metrology : Photometry
(120.5630) Instrumentation, measurement, and metrology : Radiometry
(230.3670) Optical devices : Light-emitting diodes
(150.2945) Machine vision : Illumination design

ToC Category:
Optical Devices

Original Manuscript: December 3, 2008
Revised Manuscript: January 29, 2009
Manuscript Accepted: January 31, 2009
Published: February 19, 2009

Ivan Moreno, Ching-Cherng Sun, and Rumen Ivanov, "Far-field condition for light-emitting diode arrays," Appl. Opt. 48, 1190-1197 (2009)

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  1. R. Young, “Measuring light emission from LEDs,” Proc. SPIE 6355, 63550H (2006). [CrossRef]
  2. G. Sauter and J. Schuette, “Measurement of the optical properties of LED clusters and arrays,” CIE Technical Committee TC2-50, Germany (to be published).
  3. IESNA, Photometric Testing of Indoor Fluorescent Luminaires, IES LM-41-1985 (Illuminating Engineering Society of North America, 1985).
  4. IEEE 100 The Authoritative Dictionary of IEEE Standards Terms, 7th ed. (IEEE, 2000).
  5. A. Ryer, “Light measurement handbook,” http://www.intl-light.com/handbook/ (1998).
  6. I. Moreno and C. C. Sun, “LED array: where does far-field begin?,” Proc. SPIE 705870580R (2008). [CrossRef]
  7. E. F. Zalewski, “Radiometry and photometry,” in Handbook of Optics, 2nd ed., M. Bass, E. W. Van Stryland, D. R. Williams, and W. L. Wolfe, eds. (McGraw-Hill, 1995), Vol. II.
  8. P. Manninen, J. Hovalita, P. Karha, and E. Ikonen, “Method for analyzing luminous intensity of light-emitting diodes,” Meas. Sci. Technol. 18, 223-229 (2007). [CrossRef]
  9. In a forthcoming paper we address the issue of far field for a single LED.
  10. I. Moreno and C. C. Sun, “Modeling the radiation pattern of LEDs,” Opt. Express 16, 1808-1819 (2008). [CrossRef] [PubMed]
  11. L. Svilainis, “LED directivity measurement in situ,” Measurement 41, 647-654 (2008). [CrossRef]
  12. M. Burmen, F. Pernus, and B. Likar, “Automated optical quality inspection of light emitting diodes,” Meas. Sci. Technol. 17, 1372-1378 (2006). [CrossRef]
  13. M. Bürmen, F. Pernuš, and B. Likar, “LED light sources: a survey of quality-affecting factors and methods for their assessment,” Meas. Sci. Technol. 19, 122002 (2008). [CrossRef]
  14. S. H. Jang and M. W. Shin, “Thermal analysis of LED arrays for automotive headlamp with a novel cooling system,” IEEE Trans. Device Mater. Reliab. 8, 561-564 (2008). [CrossRef]
  15. “Cree XLamp LED binning and labeling,” Application Note CLD-AP12.007, http://www.cree.com/Products/xlamp7090_xre.asp.

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