MICRO VACUUM TUBE

PURPOSE:To provide a micro vacuum tube having little cathode deterioration, and stable and approximately uniform electric characteristics. CONSTITUTION:A higher voltage than the voltage applied between a cathode electrode 2 and a main electrode 3 is applied between the cathode electrode 2 and an anode electrode 4. Further, the cathode electrode 2 is irradiate by light from EL luminescent elements 6a and 6b. Accordingly, electrons are emitted from the cathode 2 receiving energy from an electric field generated by the voltage applied between the cathode 2 and the anode 4, and the energy by light irradiation. Thereafter, the electrons are attracted by the main electrode 3, to which the higher voltage than that of the anode electrode 4 is applied, and collides with a fluorescent layer 5 formed on the main electrode 3 with a high speed so that the fluorescent layer 5 emits light.