High luminance ZnS:Mn/SrS:Ce TFEL devices

Full colour electroluminescent (EL) displays according to the "colour by white" concept are a promising candidate for various future display applications. ZnS:Mn/SrS:Ce multilayer phosphors have demonstrated their capability to fulfil the requirements of this concept. While ZnS:Mn is a standard industrial process SrS:Ce needs further improvements. Very recently, a new process to fabricate efficient SrS:Ce EL devices based on a novel S-precursor during reactive evaporation has been developed. In conventional device structures, efficiencies up to 1.4 Im/W have been obtained. Introducing this new process into a ZnS:Mn/SrS:Ce multilayer device, yellowish-white luminance level as high as 4200 cd/m2 at 1 kHz drive was reached. Driving the device at 60 Hz frequency results in following unfiltered and filtered luminances: L=340 cd/m2, Lr=39 cd/m2, Lg=90 cd/m2, Lb=18 cd/m2.