A Study of Optical Properties of a Glass Composition of a ZnO-Bi2O3-P2O5 Glass/Phosphor Composite for a White LED

For implement the white light-emitting diode (LED) package, glass-phosphor composite was produced with different glass composition and glass/phosphor ratio. To maximize the LED light emission characteristic, the glass frit was required a low firing temperature and high refractive index. We selected the bismuth phosphate glass due to their low melting and high refractive index. With further addition of Bi2O3, the value of Tg ,Ts was decrease and coefficient of thermal expansion, refractive index were increased, due to the Bi2O3 acts as modifier in the glass increasing the non-bridging oxygens. The refractive index changes of the glass frit affect the optical property of the composite. With higher contents of Bi2O3 glass composition, the transmittance and emission intensity of the composite was increased. These results suggest that the difference in refractive index between the phosphor and glass frit is minimized, the loss of light is minimized. †(Received April 1, 2014)