Abstract: A visual display has a cathode plate 101, having an emission layer 102 built up on a ceramic front layer. It has a thicker foundation layer 103. Vias from the front layer have their pitch fanned out to that of the cathode-plate back-layer vias 104.

Abstract: The front layer 1 shown in FIG. 1 is being tape cast in the direction of the arrow A from alumina ceramic material 2 onto a mylar layer 3. The doctor blade 4, which regulates the thickness T of the ceramic layer has serrations 5, which form parallel grooves 6 in the front surface 7 of the layer. After the material has set, by evaporation of the moisture allows the material to be sufficiently fluid for its casting, vias apertures 8 are punched in it, whilst it is still supported on the mylar, FIG. 2. They are filled with via material 9, FIG. 3, as described in more detail below. After via filling, the mylar layer is peeled from the tape cast ceramic.

Abstract: A display has a cathode 1 and an anode 2. These are in plate form and held spaced apart by a peripheral frame 3, to which they are both sealed. The cathode has an emission layer 11 deposited on a front ceramic layer 12 with vias 14 to the emission layer. The foundation layer is fired, ground flat and has via apertures cut through it and filled 17 prior to lamination of the front layer. Onto the back face of the substrate, preferably prior to deposition of the emission layer, is spun on a dielectric layer 21, which is developed with the aid of a temporary mask (not shown) to provide etchable tracks. These are etched to leave grooves 22 corresponding to metallic interconnections 23 from the foundation layer vias 17 to vias 24 in the next dielectric layer 25, typically thicker than the previous one 21. The metallic interconnections 23 are formed by screen printing and firing.