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Applied Optics

Applied Optics


  • Editor: Joseph N. Mait
  • Vol. 49, Iss. 1 — Jan. 1, 2010
  • pp: 12–20

Light-emitting diode spherical packages: an equation for the light transmission efficiency

Ivan Moreno, David Bermúdez, and Maximino Avendaño-Alejo  »View Author Affiliations

Applied Optics, Vol. 49, Issue 1, pp. 12-20 (2010)

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Virtually all light-emitting diodes (LEDs) are encapsulated with a transparent epoxy or silicone gel. Here we analyze the optical efficiency of spherical encapsulants. We develop a quasi-radiometric equation for the light transmission efficiency, which incorporates some ideas of Monte Carlo ray tracing into the context of radiometry. The approach includes the extended source nature of the LED chip and the chip radiance distribution. The equation is an explicit function of the size and the refractive index of the package, and also of several chip parameters such as shape, size, radiance, and location inside the package. To illustrate the use of this equation, we analyze several packaging configurations of practical interest, for example, a hemispherical dome with multiple chips, a flat encapsulation as a special case of the spherical package, and approximate calculations of an encapsulant with a photonic crystal LED or a photonic quasi-crystal LED. These calculations are compared with Monte Carlo ray tracing, giving almost identical values.

© 2010 Optical Society of America

OCIS Codes
(030.5620) Coherence and statistical optics : Radiative transfer
(080.2740) Geometric optics : Geometric optical design
(120.5630) Instrumentation, measurement, and metrology : Radiometry
(230.3670) Optical devices : Light-emitting diodes

ToC Category:
Optical Devices

Original Manuscript: May 27, 2009
Revised Manuscript: September 21, 2009
Manuscript Accepted: November 17, 2009
Published: December 21, 2009

Ivan Moreno, David Bermúdez, and Maximino Avendaño-Alejo, "Light-emitting diode spherical packages: an equation for the light transmission efficiency," Appl. Opt. 49, 12-20 (2010)

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