Rare earth ions doped luminescence glasses are promising phosphor candidates in the fabrication of LEDs in the future due to their specific advantages such as higher thermal stability, higher transparency, compared to current commercial LEDs. While radiation patterns of luminescent glasses are different from current commercial LEDs fabricated by phosphors, luminescent glasses play roles both in emitting light and adjusting light distribution. In order to investigate radiation pattern of luminescent glasses, luminescence physical model of flat glasses doped with single rare earth ion was presented. Process of photons acting on rare earth ions and transporting in the luminescent glasses, and output light distribution from luminescent glasses were analyzed based on violet LED. At last, the simulating of radiation pattern for luminescent glasses based on Monte Carlo ray-tracing method was proved by experiment.
The experimental excitations for luminescent glasses are usually monochromatic, but LED chips in applications have an emission bandwidth. In order to investigate the luminescence properties of rare earth ions doped glasses excited by broadband lights, a computational model was presented based on the dependences of excitation wavelengths on emission spectra, chromaticity coordinates and correlated color temperatures (CCTs). The simulations were carried out applying Ce/Tb/Eu co-doped calcium borosilicate glasses as examples. The results show that for the same CCTs, the center wavelengths of chips are different with the excitation wavelengths of fluorescence spectrophotometers.
Quantum efficiency measurement of luminescence glasses for high-power white LED was investigated. Luminescence
glasses have transparent and anisotropic characteristics, for this reason, we adopted an integrating sphere with 20cm
diameter which was connected to a CCD spectrometer to obtain fluorescence spectra of the sample. The relative spectral
intensity distribution of the sample under the light source excited was derived from the measured spectra firstly, then
using the standard halogen lamp to calibrate the system, we got the absolute spectral intensity distribution, finally the
quantum efficiency of the sample can be calculated based on the distribution. It provides an accurate method to measure
the luminescence materials’ emission characters.