Operating a Gas Discharge Panel (01-May-1970)

Operating a Gas Discharge Panel

The gas-discharge panel operates by applying pump voltages which are the same for all elements in a column of a matrix rut are delayed in time with respect to the pump voltage supplied to any other column of a gas-discharge matrix. Drawing A shows a representative portion of the row and column, X and Y, select lines of a panel. Drawing B shows the pump signals which are applied to the designated columns. The gas discharge panel consists of gas chamber 1 and row and column select lines X...X + 3 and Y...Y + 3, respectively disposed in a coordinate array. The chamber is filled with an appropriate gas such as neon- nitrogen or neon-argon which, upon the application of appropriate voltages to the row and column select lines, ignites to form a visible glow discharge. The potential difference required for ignition is somewhat greater than the pumping or sustaining voltage which is usually applied to maintain the previously ignited cells in a glowing state. The waveforms shown in B are applied in sequence to the columns Y...Y + 3 and as such periodically sustain previously ignited gas cells associated with the column being activated at any instant.

There are several advantages realized from such a panel. In the sustain mode, if some cells of the panel are written, they are sustained, i.e., continue to fire once each time the pump signal of B reverses polarity. Cells which are not written remain off since the pump voltage is less than the ignition or firing voltage. The advantage of this technique over other techniques is that only one row is fired at any one time. In this system, only the cells of one column fire at one time and the addressing leads for the columns can be put on the rack panel and thus made as thick as necessary to decrease their resistance. The row address lines are placed on the front but, since only one point in the row fires at a time, they can have a fairly high resistance and can thus be very tra...