Cold cathode and method for operating the same

摘要

A method is applied for operating a cold cathode having at least one electron emission portion and a control electrode for controlling an emission of electrons, in which an electron beam is extracted out of the cold cathode by applying operating voltages to the electron emission portion and the control electrode, respectively. At least one auxiliary electron emission portion is provided other than the electron emission portion positioned at an operating position for emitting electrons. In order to replace the electron emission portion to be operated, the electron emission portions are moved so that the auxiliary electron emission portion is positioned at the operating position.