Plasma addressing for flat-panel displays

An active-matrix technique that is functionally identical to an array of thin-film transistors (TFTs) but does not rely on semiconducting materials or the manufacturing processes normally associated with integrated circuits is described. The approach avoids the manufacturability problems that have hampered the development of large TFT displays. The new addressing technology relies on the properties of a confined, ionized gas, and is called plasma addressing (PA). It uses the gas to perform electrical switching. When the gas is in an ionized state, it is conducting; when in a deionized state, it is nonconducting. The difference between the conductivity of the gas in its conducting and nonconducting states is easily 10 orders of magnitude. When the cathode voltage is switched on and the gas is ionized, a properly located probe electrode appears electrically connected to the anode, which can be at ground potential. When the cathode voltage is reduced below the plasma sustaining voltage, the plasma is extinguished and the probe electrode is no longer connected to the anode. Thus, the cathode connection can be thought of as a control or ´gate´ electrode. PA has been used to address twisted nematic and polymer-dispersed liquid crystals. The technology´s inherently wide voltage range also allows it to be used for addressing thin-film electroluminescent films.<>