Improved Sputter-Resistant Encapsulated Cathode Lateral DC PDP Structure

Summary form only given. We report a novel encapsulated cathode lateral DC pixel structure suitable for realization of plasma display panels. The structure consists of laterally placed cathode and anode electrodes on a single substrate where the isolation of the electrodes is possible by an insulating layer such as liquid glass. The cathode in this paper is encapsulated in a tunnel-like structure where one side of the tunnel is opened and the cathode electrode is placed on the other end (closed side) of the structure. The anode is placed opposite to the cathode on the same substrate. The encapsulated cathode protects the metallic electrode from being bombarded by plasma ions, hence minimizing the sputtering of the electrodes. Fabrication of our DC-PDP starts with depositing of a 0.3 mum thick chromium layer on a glass substrate. After patterning the chromium layer to form X-addressing lines, a sacrificial layer of copper (or polymers) is deposited with a thickness of 2 mum to act as a "mold" for the future tunnel. After proper patterning the copper sacrificial layer, the whole substrate is coated by an insulating layer (oxide or liquid-glass) and the sample is cured under ultra-violet illumination. The insulating layer is then patterned to open windows just on one side of the copper sacrificial layer. Once the windows in glass are opened, the sample is immersed in the copper solvent to remove the copper from underneath of the insulating oxide layer. In this way, there will be an offset between the cathode (Cr) and the opening of the encapsulating tunnel. The fabrication of the main substrate is finalized by depositing and patterning the second electrode (silver) to form the anode electrode. Such patterns are placed perpendicular to the cathode lines to realize an X-Y matrix. By applying proper voltage between cathode and anode electrodes, plasma is generated and pixel is turned on. Pixel size is 400 mum by 600 mum and top substrate (which carries the barrier waffle- ) can be placed on top of the main substrate to complete the panel. Preliminary measurements indicate the proper action of the encapsulating cathode in preventing any damage to the cathode due to an intense plasma generation. Turn-on voltage is around 420 V at 300 torr of argon as the test gas. We have also realized display panels using lateral structures on both glass and plastic (PET) substrate and various images have been obtained and will be reported. The addressing of pixels in our panels is achieved using external series resistance at each line. By proper designing the mask sets for pixel processing, we speculate that hollow-cathode structures are feasible in which the lateral encapsulating tunnel is long with a small opening at the end. This technique removes the need for a series resistance in each pixel and extends the life of phosphors and electrodes. Fabrication of a medium size panel is underway. Also results on flexible bases are reported.