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Proceedings Paper

Numerical modeling and uncertainty analysis of light emitting diodes for photometric measurements
Author(s): Mohammed Z. U. Khan; Mohammed Abbas; Luai M. Al-Hadhrami
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Paper Abstract

With the rapid evolution of new, energy-efficient solid-state lighting (SSL) systems, a requirement has risen for new performance metrics and measurement methods to address their unique construction and operating conditions. In this paper, light propagation characteristics in light emitting diodes are analyzed for measurement uncertainty through numerical modeling and simulation. A general 2D EM simulator with PML boundary conditions is formulated to solve Maxwell's equations using finite-difference time domain (FDTD) numerical method to describe the light propagation in LEDs.

A practical GaN LED used in SSL systems is simulated for light propagation. The optical properties of dispersive materials are modeled using multi-pole Lorentz-Drude model. The input dipole source for the LED structure is modeled explicitly through a Gaussian pulse line source at a central wavelength of 460 nm corresponding to GaN emission. Finally, the expression for combined standard uncertainty in the light extraction efficiency due to uncertainties in inputs such as emission in the active layer and EM fields is developed using the GUM law of propagation of uncertainties. The uncertainty in GaN LED emission wavelength obtained from Full Width Half Maximum (FWHM) of the emission spectrum is computed to be 16.98 nm. Therefore, the uncertainty analysis model is then used to compute the corresponding uncertainties in the LED output measurements i.e. light extraction efficiency, LED output power and EM fields.

Paper Details

Date Published: 21 June 2015
PDF: 12 pages
Proc. SPIE 9526, Modeling Aspects in Optical Metrology V, 95260F (21 June 2015); doi: 10.1117/12.2183599
Show Author Affiliations
Mohammed Z. U. Khan, King Fahd Univ. of Petroleum and Minerals (Saudi Arabia)
Mohammed Abbas, King Fahd Univ. of Petroleum and Minerals (Saudi Arabia)
Luai M. Al-Hadhrami, King Fahd Univ. of Petroleum and Minerals (Saudi Arabia)

Published in SPIE Proceedings Vol. 9526:
Modeling Aspects in Optical Metrology V
Bernd Bodermann; Karsten Frenner; Richard M. Silver, Editor(s)

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