PURPOSE: To actuate a field emission type cathode for a long time stably by applying metal powder having a higher melting point than a specific temperature on a joint part of a single crystal wire with a heating filament, and sintering the metal powder for supporting the joint part.
CONSTITUTION: On a joint part of a high melting point metal single wire 1 of tungsten or the like with a filament 2, metal powder 3 of zirconium or the like having a melting point which is lower than the melting point of the wire 1 and the filament 2 and which is 1800K or more is applied. This is then heated and sintered to harden the powder 3. The single crystal wire 1 and the filament 2 are thus joined together, and conductivity is provided. Generation of defects such as those in spot welding will not occur in the single crystal wire 1, thereby current stability, service life, and reliability of a cathode are improved.
SHINADA HIROYUKI
OSHIMA TAKU
KURODA KATSUHIRO
