AVS 46th International Symposium
    Flat Panel Displays Topical Conference Monday Sessions
       Session FP+VT-MoM

Invited Paper FP+VT-MoM10
Hermetic Sealing and Evacuation of Candescent's ThinCRT@superTM@

Monday, October 25, 1999, 11:20 am, Room 604

Session: Field Emission Displays and Vacuum Packaging Issues
Presenter: T.S. Fahlen, Candescent Technologies Corporation
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Candescent has developed a full color, full video, power efficient display, the ThinCRT@superTM@ based on Spindt-type field emitters with very low voltage switching (<10.5 volt), and "high voltage" (6 KV) aluminized phosphors. Because of the high voltage used, the faceplate (anode/phosphor screen) and backplate (cathode) of the display are separated by 1.25 mm. This talk describes two methods used to hermetically seal the perimeter and evacuate ThinCRT displays. In both methods, the faceplate and backplate are sealed to a frame made of glass frit placed between them following an accurate, room temperature and atmospheric pressure alignment procedure. One sealing method uses a laser to first seal the frit frame to the faceplate, and then to hermetically seal the backplate to this assembly in a vacuum environment; no exhaust tubulation is required, and a non-evaporable getter is incorporated along one internal border of the display. A second method uses a laser to seal the frit frame to the faceplate, and the backplate to the frame/faceplate assembly but in a non-vacuum environment. An auxiliary chamber (AC) containing a getter and exhaust tube is then oven sealed to the rear of the assembly. Holes in the backplate allow the gases in the interior of the display to flow into the AC. The display assembly is then evacuated through an exhaust tubulation. The AC saves border space by allowing the getter to be removed from the display border to the rear of the display. The AC adds no additional thickness to the display because it protrudes no further than do the display electronics which are also attached to the rear of the display. In both sealing methods, the exact spacing between the faceplate and the backplate is determined solely by the internal support structure. The frit frame and sealing process have been designed so that during laser sealing, the frit expands to fill and seal the small gap left between the frit frame and the faceplate.