| 摘要 |
<p>PURPOSE:To perform electron emission stably for a long period of time by colliding a part of the electron omitted from an emitter of another emitter which is not in an emission condition, so as to perform cleaning of the emitter. CONSTITUTION:When an electron e1 is emitted from an emitter 4 or an emitter group provided on one emitter electrode 3 divided, under a normal electric field condition, a positive electric potential of at least the same or greater as/than the electric potential of a gate 7 is applied to the other emitter 5 or an emitter group. When the emission is carried out by the other emitter 5, a preset positive electric potential is given to the emitter 4. By driving in this way, the electron e1 injected form one emitter 4 collides with the other emitter 5, which is cleaned thereby, and an electron e2 emitted from the other emitter 5 cleans the emitter 4. Stable electron emission is thus possible for a long period of time.</p> |
