Abstract: A highly efficient, AC-excited, blue light-emitting phosphor for solid-state thin-film electro-luminescent (TFEL) devices is comprised of strontium sulphide (SrS) host material doped with cerium fluoride (CeF.sub.3) acting as an emitter providing a source of photons. The blue SrS:CeF.sub.3 phosphor is about one hundred times brighter than the brightest zinc sulphide/thulium fluoride (ZnS:TmF.sub.3) blue phosphor heretofore known. To increase brightness level, at some loss of energy efficiency, electron-injection layers of zinc sulfide (ZnS) are placed on either side of the SrS:CeF.sub.3 layer in the TFEL device.

Abstract: A novel TFEL structure for providing a reliable, high performance multi-colored matrix-addressable flat screen display. The structure comprises a multi-layered panel consisting of two or more TFEL subpanels stacked one on top of the other, with each subpanel utilizing a light-emitting phosphor of a different color. All the layers in the composite structure (with the possible exceptions of the supporting substrate layer and the electrode and insulating layers located farthest from the viewer) are transparent, and the multi-layered subpanels are supported on respective substrates and connected by spacers to maintain the subpanel components in predetermined close proximity. The intervening space between the component panels is filled with a protective oil to improve the performance and optical characteristics of the device. The oil may also be dyed to serve as a filter modifying the light emission characteristics of the composite display device.

Abstract: A TFEL panel includes orthogonally disposed sets of scanning and data electrodes. The scanning electrodes are strobed with a preconditioning voltage and data is provided to selected data electrodes simultaneously with the line by line strobing of the scanning electrodes. A refresh pulse is applied to the screen once per frame of data at times which vary from frame to frame. This may be accomplished either by varying the time of occurrence of the refresh pulse within each frame or by holding the time of occurrence of the refresh pulse constant and varying the strobing sequence of the scanning electrodes. This technique prevents certain portions of the screen from generating a latent image due to charge accumulation which would otherwise result from the timing asymmetry between the scanning of certain electrodes and the fixed timing of the refresh pulse.