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Spot phosphor concept applied to the remote phosphor configuration of a white phosphor-converted LED

Boekbijdrage - Boekhoofdstuk Conferentiebijdrage

Phosphor-converted lighting devices based on solid state technologies are ubiquitous in applications such as general lighting, displays and signalization. The further need of improvement in the efficiency of these applications demands realistic simulation models to accelerate the optimization processes. This work reports on the adoption of the inverse adding doubling (IAD) method for the determination of the optical parameters of a phosphor element and its later usage as input in the bulk scattering, absorption and fluorescence model defined in the ray tracing simulation software LightTools. For the IAD method, the measurement of the total transmission, total reflection and regular transmission are needed in order to determine the optical parameters (scattering coefficient µs, absorption coefficient µa and the phase function coefficients g and α). The phosphor element consists of a YAG:Ce-silicone oil solution with a phosphor concentration of 100 mg/ml, immersed in a glass cuvette with a gap between glasses of 1.1 mm. The phosphor element is illuminated by blue (450 nm) and yellow (580 nm) light and characterized using a spectral goniophotometer, offering the complete angular spectral radiant intensity in reflection and transmission and, thereby, the integrated spectral reflectance and transmittance values. Besides, a custom-made integrating sphere is used to measure both the absolute quantum efficiency and the emission spectrum at 450 nm excitation wavelength. There is a good correspondence between the experimental and the simulated results of the spectral radiant intensity in reflection and transmission, as can be concluded from the evaluation of the normalized cross correlation function (NCC) (NCC>0.97) and the normalized root-mean-square error (NRMSE) (NRMSE<5.4%). Furthermore, the resulting values for the power balance calculations exhibit relative differences smaller than 5 % between experimental and simulation data for each of the light interactions, i.e. blue incident-blue scattered, blue incident-yellow scattered and yellow incident-yellow scattered.
Boek: Optical Modelling and Design IV
Aantal pagina's: 8
ISBN:9781510601345
Jaar van publicatie:2016
BOF-keylabel:ja
IOF-keylabel:ja
Authors from:Higher Education