Abstract: The present invention is directed to a modified cover plate for a thin film electroluminescent display device. The cover plate of the present invention is provided with at least two diagonally disposed fill holes and complementary fill tubes. In the upper plane of the cover plate, the fill holes each comprise two concentrically positioned recesses, the outer one of which is of larger diameter, but smaller depth than the inner. Conversely, the inner recess is of smaller diameter, but larger depth than its concentric counterpart. In the lower plane of the cover plate, the fill holes are each provided with a pair of concentrically positioned recesses which complement those in the upper plane. At the planar junction of each of the smaller diameter (inner) recesses there is formed a passageway through the cover plate. The fill tubes are designed to be retained by the fill holes without adversely impacting the dimensional thickness of the panel.

Abstract: A hermetically sealed enclosure for a thin film device, such as an electroluminescent device, in which the device includes a thin film matrix supported on a glass substrate. The glass substrate is mounted in a frame and a frit seal is provided between the glass substrate and the frame. A cover is also secured and sealed to the frame by a weld or solder joint. The integrity of both the substrate to frame seal and the frame to cover seal is preserved by forming the surfaces bounding each seal out of materials having substantially similar coefficients of thermal expansion. Since the rates of expansion will be similar, the seals should not develop weaknesses throughout the life of the device over a range of temperatures.

Abstract: An improved hermetic seal means for use in an electroluminescent display device for joining the protective cover sheet (glass) over the base substrate. The base substrate has typically deposited thereon multiple thin film layers. The hermetic seal comprises an electrically insulative thin film layer disposed over the conductive thin film leads associated with the multiple thin film layers, and metallic solder means over the insulative thin film layer to provide a bond between the cover sheet and base substrate.

Abstract: An improved dark field material for use in a thin film electroluminescent display device that typically includes a transparent electrode layer, a segmented electrode layer and an electroluminescent phosphor layer between the electrode layers. The improved dark field layer is of a composition of a dielectric material such as the preferred magnesium oxide and a noble metal, which is preferably gold co-evaporated by way of an electron beam deposition technique. The preferred range of noble metal by volume is 6%-10%. By varying the noble metal content within this range, there is provided control of the operating temperature of the electroluminescent display device.

Abstract: A contrast enhanced electroluminescent device employs a chromium oxide-chromium cermet as the contrast enhancing material.

Abstract: An improved apparatus and method for making solid filamentary elements from a pendant drop of a high melting point material (e.g. hafnium, zirconium). The improvement constitutes providing a protective layer in the form of a thin film on the circumferential edge of the casting wheel prior to engagement of the drop and release of the elements. The layer material serves to reduce heat flow from the drop material to the wheel as well as prohibit bonding of the drop material thereto. The preferred layer materials are aluminum, carbon (e.g. graphite), boron nitride, and borosilicate glass.

Abstract: A dichroic coating is deposited on a cylindrical lamp envelope from an evaporation source while the envelope is heated and rotated. The thickness of the coating is monitored by measuring the intensity of light beamed on and reflected from a flat plate in line of sight with the evaporation source.