| 摘要 |
<p>An electron emission system includes a high-brightness field-emitter cathode (10). Advantageously, the tip (22) of the cathode is shaped to minimize structural variations caused by surface tension forces. In addition, an electrode assembly (30, 34) associated with the cathode (10) is designed to establish electric field forces that are opposite and at least approximately equal to the surface tension forces acting on the tip. The electric field forces can be adjusted to establish a highly stable operating condition without altering the value of electron beam energy for which the overall system was designed. Moreover, the current density of the beam (42) at a writing surface can be selectively varied without changing prescribed operating parameters of the cathode (10). The resulting system is characterized by excellent emission stability, low noise and a useful operating life of at least several thousand hours.</p> |
