Structure and fabrication of gated electron-emitting device having electron optics to reduce electron-beam divergence

摘要

An electron emitter contains a gate layer (38), an underlying dielectric layer (36), an intermediate non-insulating layer (34) situated below the dielectric layer, and a lower non-insulating region (32) situated below the intermediate non-insulating layer. A multiplicity of electron-emissive particles (42) are situated over the non-insulating region at the bottom of an opening (40) extending through the three layers. The ratio of the thickness of the dielectric layer to the thickness of the intermediate non-insulating layer is in the range of 1:1 to 4:1, while the ratio of the mean diameter of the opening to the thickness of the intermediate non-insulating layer is in the range 1:1 to 10:1. The presence of the intermediate non-insulating layer improves the collimation of the beam of electrons emitted from the electron-emissive elements. The electron emitter is manufactured according to a simple, readily controllable process.