. . . "In the various field emission device, the material for constituting a cathode electrode can be selected from metals such as tungsten (W), niobium (Nb), tantalum (Ta), titanium (Ti), molybdenum (Mo), chromium (Cr), aluminum (Al) and copper (Cu), gold (Au), silver (Ag) and the like; alloys and compounds containing these metal elements (for example, nitrides such as TiN and silicides such as WSi2, Mo" . . . . . . . . . .