| abstract |
A raw material prepared by washing a phosphor powder containing a phosphor host material and an activator with an acid solution, followed by drying the washed powder, is heated within a thermal plasma at a temperature which permits partially melting the phosphor, followed by cooling and subsequently subjecting the resultant phosphor at 1200 DEG to 1700 DEG C., thereby manufacturing spherical phosphor particles having a concentration gradient in a radial direction. |