A glow discharge matrix display tube

A new glow discharge display tube is described for presenting in-line alphanumeric characters, which gives a brighter and clearer display than presently available tubes. It is based on a novel cathode construction, whereby the cathode is positioned at the base of a recess in a glass surface. The negative glow on a cathode which has been recessed in this manner is bright and well-defined. Even at current densities which are more than adequate for display purposes, sputtered material from the cathode is trapped within the recess and does not blacken a closely-spaced viewing window but on the other hand maintains stable characteristics. The tube, thus, has a long operational life, and brightnesses in excess of 600 foot-lamberts are readily available.