Fabrication of YAG glass ceramic and its application for light emitting diodes

In this paper, we present our recent research on phosphor glass ceramic technology, consisting of a ceramic plate of Ce (III) doped yttrium aluminum garnet (YAG:Ce) YAG glass ceramic. The glass ceramic is fabricated through high temperature solid state reaction method, and is detected to confirm crystal phase by SEM and XRF. The white light is successfully observed by packaging the glass ceramic slice to the blue LED chip. The ceramic packaged LED sample shows relatively lower CCT than the conventional phosphor dispensing LED sample. Controllable optical and geometrical properties of the YAG glass ceramic plate will bring about distinctive improvement in manufacturing of identical CCTs for high power white LEDs. The combination of phosphor ceramic slice with blue LED chip of a specific wavelength, if measured before the final assembly, enables targeted production of specific CCT white LEDs. The phosphor glass ceramic technology can be utilized for the combination with the thin flip chip LED technology, which permits a direct bonding of the ceramic slice to the light source surface of the LED. It is expected that this glass-ceramic is a promising candidate.