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Light-emitting diodes (LEDs) are becoming increasingly important for general lighting applications. The remote phosphor technology, with the phosphor located at a distance from the LEDs, offers an increased extraction efficiency for phosphor converted LEDs compared to intimate phosphor LEDs where the phosphor is placed directly on the die. Additionally, the(More)
An integrating sphere-based setup to obtain a quick and reliable determination of the internal quantum efficiency of strongly scattering luminescent materials is presented. In literature, two distinct but similar measurement procedures are frequently mentioned: a "two measurement" and a "three measurement" approach. Both methods are evaluated by applying(More)
Luminescent materials are widely used in white LEDs to convert part of the blue LED light into light with a longer wavelength, resulting in white light when both colors are well mixed. One way to integrate the luminescent material in the LED package is to deposit a thin luminescent layer on a planar carrier or disperse luminescent particles in the carrier(More)
To perform adequate simulations of luminescent cascade systems, a hybrid method combining a commercial ray tracer and a programming tool is presented. True Monte Carlo algorithms for luminescent materials, treating each ray individually, are adapted to allow wavelength conversion of ray sets. Two solutions for the wavelength conversion of ray sets are(More)
Remote phosphor light-emitting diode (LED) modules could offer advantages over intimate white phosphor converted LEDs in terms of phosphor operation temperature, light extraction efficiency, and angular color uniformity. Existing commercial devices show a large variety with respect to the dimensions of the mixing cavity, which raises a question about the(More)
The extension of a well-known inverse technique, inverse adding-doubling (IAD), is investigated for determining the volume scattering properties of diffusers for display and lighting applications. The luminance characteristics of volume scattering diffusers are vital for these applications. Through a simulation study, it is shown that fitting solely to the(More)
In this paper a fast, yet accurate method to estimate the spectral and angular distribution of the scattered radiation of a fluorescent material is described. The proposed method is an extension of the adding-doubling algorithm for non-fluorescent samples. The method is validated by comparing the spectral and angular transmittance and reflectance(More)
To enhance the efficiency of solar cells, a luminescent down shifting layer can be applied in order to adapt the solar spectrum to the spectral internal quantum efficiency of the semiconductor. Optimization of such luminescent down shifting layers benefits from quick and direct evaluation methods. In this paper, the potential of the adding-doubling method(More)
The accuracy of optical simulations including bulk diffusors is heavily dependent on the accuracy of the bulk scattering properties. If no knowledge on the physical scattering effects is available, an iterative procedure is usually used to obtain the scattering properties, such as the inverse Monte Carlo method or the inverse adding-doubling (AD) method. In(More)
In this paper, the design of an inexpensive integrating sphere setup is presented, enabling students to perform optical characterization of light sources with reasonable accuracy, in a student laboratory context. Instead of using an expensive sphere with magnesium oxide or barium sulfate coating, a cheap polystyrene sphere is employed. In combination with a(More)