Yellow ZnS-based phosphor, process of preparing the same and display device using the phosphor

A yellow ZnS-based phosphor which has improved color coordinates and luminance for use in intermediate- and low-voltage display devices using improved activators and coactivators is a (ZnS: Mn, Cu) phosphor which has color coordinates (x, y) shifting to a yellow emission as the amount copper added as an activator is increased. The phosphor has enhanced luminance by adding a trivalent metal as a coactivator. Therefore, the (ZnS: Mn, Cu) phosphor can be advantageously utilized for various display applications including vacuum fluorescent displays (VFDs) and field emission displays (FEDs).