US Patent 7825436 Thin film electron source

A thin film electron source comprising a substrate, a lower electrode formed on one main face of said substrate, an insulation layer formed in contact with said lower electrode and an upper electrode formed in contact with said insulation layer. The upper electrode comprises a first under-layer, a second under-layer, an intermediate layer and a surface layer laminated from the insulation layer side. A main material of the first under-layer is IrO2 or RuO2; a main material of the second under-layer is Ir or Ru, and a main material of the surface layer is a member selected from the group consisting of Au and Ag.