(under subclass 33) Subject matter wherein the cathode-ray tube has an annular anode coated with fluorescent material surrounding an emissive center cathode and a control electrode for varying the width of the discharge between the cathode and anode so that as the potential of the control electrode varies the width of the nonluminous portion of the anode varies.
SEE OR SEARCH CLASS
313, Electric Lamp and Discharge Devices,
107.5, for magic eye indicating tubes, per se.
324, Electricity: Measuring and Testing,
121, for electrical measuring, testing or sensing circuits, per se, in which a magic eye tube is used.
