thereof is present the plates are bonded together at the periphery using a state of the art microelectronic bonding technique such as low temperature alloy sealing or glass frit sealing davidson u s pat no 4 563 617 teaches use of a faceplate attached around the mutual perimeter of a substrate assembly to provide a hermetic enclosure this procedure could be used to seal the non viewing side of the device in a preferred gas horstey et al u s pat no 4 095 876 describes a metal coated around the periphery of a display panel and added soldering for bonding dabral u s pat no 5 781 858 describes a similar metalized hermetic sealing method to eliminate bulb blackening and for redepositing evaporated w back onto thin spots of the electrodes bromotrifluoromethane cbrf3 is a recommended gas additive this gas ambient additive allows the fluoride component to aid redeposit of the tungsten back onto hot spots on the electrodes thus providing a u201c self healing u201d action in addition the c component reacts with oxygen in the enclosure forming a stable compound of co2 tying up any residual oxygen in the hermetic enclosure see for example u201c chemical equilibrium calculations of tungsten halogen systems u201d j a sell j appl.