| 摘要 |
<p>An electron source includes a negative electron affinity photocathode (10) on a light-transmissive substrate (12) and a light beam generator (50) for directing a light beam (22) through the substrate (12) at the photocathode (10) for exciting electrons into the conduction band. The photocathode (10) has at least one active area for emission of electrons with dimensions of less than about two micrometers. The electrons source further includes electron optics (32, 66) for forming the electrons into an electron beam (30) and a vacuum enclosure (14, 62) for maintaining the photocathode (10) at high vacuum. The photocathode (10) is patterned to define emission areas. A patterned mask may be located on the emission surface of the active layer, may be buried within the active layer or may be located between the active layer and the substrate (12).</p> |
