Development in Phosphor Glass Ceramic Composites

Glass ceramics containing phosphor, GCP, has become an advanced material in high power LED lighting application recently due to its superior optical and thermal performance and elongated lifetime. Glass systems which have lower characteristic temperatures , glass transition temperature(T_g) and glass softening point(T_d)…, as well as excellent mechanical strength and chemical stability, are proposed in microelectronics technology, infrared laser technology and sealing of materials. Borosilicate glass systems exhibit lower characteristic temperatures and quality optical properties. By controlling functional elements, further enhancement in thermal, mechanical, and optical properties can deduced. In this study, the YAG phosphor powders embed into designed glasses under controlled atmosphere to from glass ceramics phosphor composites. The thermal, optical properties and structure of borosilicate glass host are discussed. Heat treatment which affects the YAG phosphor incorporation into the glass is also considered. The glass transition temperatures(T_g) and softening points(T_d) are 447~483^oC, and 476~524^oC respectively. A high refractive index of 1.85~1.94 can be reached. The results show that the developed borosilicate glass hosts are suitable for GCP matrix to contain phosphor powders. The YAG phosphor powders are well contained and dispersed in the glasses.

Key words: LED, Glass ceramics phosphor composites(GCPC), Low characteristic temperature, Heat treatment