Abstract: An electron tube cathode has a composite suppression layer structure interposed between the base metal and the electron-emitting material to suppress an interface layer formed through the reaction of the base metal with the electron emissive material. The composite layer structure includes a thin layer of Pt or Re and a layer of oxide of Zr and/or Hf. As a result, the formation of the interface layer is prevented so that the useful life of the electron tube cathode is prolonged.

Abstract: An electron tube cathode in such a structure comprising a Ni-W-Zr alloy (W content: 20-28 wt. %) having a grain size of 4-10 .mu.m as a base metal, a 1,000-2,000 A-thick Pt film provided on the surface of the base metal, and an electron emitting material layer consisting of alkaline earth metal oxide provided on the Pt film has less emission lowering and less peeling of the electron emitting material layer, even if placed in a long time service. The electron tube cathode can be produced according to a method comprising (i) a step of annealing a base metal of Ni-W-Zr alloy (W content: 20-28 wt. %) at 1,000.degree.-1,200.degree. C., (ii) a step of providing a 1,000-2,000 A thick Pt film on the surface of the base metal, and (iii) a step of providing an electron emitting material layer consisting of alkaline earth metal oxide on the Pt film.

Abstract: A thin-film field-emission electron source having an emitter within a minute cavity in a conductive substrate, an insulating layer covering the surface of the substrate except for the portion of the cavity, and a first anode layer on the insulating layer, wherein the substrate and the emitter are comprised as one body, and the insulating layer and the first anode layer overhang the cavity, except directly over the emitter.This electron source may be manufactured by the method comprising the steps of i) forming a sandwich structure of the substrate-insulating layer-first anode layer, ii) forming a closed loop opening at a predetermined position on the surface of the first anode layer, iii) etching the insulating layer with the use of the first anode layer as a mask and iv) forming an emitter and a cavity by etching the substrate with the use of the insulating layer as a mask.