Precise optical modeling for silicate-based white LEDs

Precise optical model of multi-chip white LEDs.

A single-chip white light LED is commonly modeled by considering the phosphor coating as a homogeneous Lambertian light source. However, this approach leads to an incorrect optical simulation of phosphor-coated multi-chip LEDs due to the presence of a previously unreported spatial distribution of emission spots across the phosphor layer. We introduce "weighting" factors based on position-depend...

Nanophosphors for White Light Leds

Precise slit-width control of niobium apertures for superconducting LEDs.

We introduce a novel three-step procedure for precise niobium (Nb)-etching on the nanometer-scale, including the design of high contrast resist patterning and sacrifice layer formation under high radio frequency (RF) power. We present the results of precise slit fabrication using this technique and discuss its application for the production of superconducting devices, such as superconductor-sem...

The Mixed Blessing of Phosphor-Based White LEDs

Light-emitting diodes (LEDs), which use less energy and last longer than even compact fluorescent lights, 1 are predicted to become the leading lighting technology in the United States as incandescent bulbs are phased out. 2 But Abraham Haim, director of the Israeli Center for Interdisciplinary Studies in Chronobiology, will not bring white LEDs and other so-called short-wavelength lights into ...

New Silicate Phosphors for a White LED

We focus on the development of new silicate phosphors for a white LED. In the europium doped silicate system, four LED phosphor candidates—Li2SrSiO4:Eu, Ba9Sc2Si6O24:Eu, Ca3Si2O7:Eu and Ba2MgSi2O7:Eu were found. Luminescent properties under near UV and visible excitation were investigated for the new Eu2+ doped LED silicate phosphors. These new phosphors have a relatively strong absorption band...