| 摘要 |
<p>17 Thermionic cathode and method of manufacturing same. The cathode has a layer structure, in which the individual layers which consist substatially alternately of emitter material (2) and base material (1) are provided at an oblique angle to the macroscopic emitting cathode surface. In a preferred embodiment the surface shows microscopically a stepped structure in which the run-out steps form the continuation of the emitter material layers. In a further embodiment the surface is not stepped but is formed by a polycrystalline or a preferentially oriented polycrystalline coating layer which is provided on the succession of beveled layers. The succession of layers is manufactured by alternating depositions from the gaseous phase associated with subsequent bevel grind of the layers. The polycrystalline coating layer is again provided by deposition from the gaseous phase. The stepped surface is formed, for example, by selective structure etching after the bevel grind. Figure 1.</p> |
