Far-field studies on Eu3+-doped lithium aluminoborate glass for LED lighting

The luminous intensity distribution from luminescent glass disks is investigated. For this, the disks are placed on top of an ultraviolet and a blue LED and the emission from the optically-activated glass is recorded in the far field. The luminous intensity distribution of the LED light and the Eu luminescence is considered separately by filtering the LED excitation, the same applies to the measured total luminous flux. Angle-dependent spectra are also measured and the changes in color coordinates are examined versus the viewing angle. The experimental results of the luminous intensity distribution curves are compared with ray-tracing simulations.