| 摘要 |
<p>PURPOSE:To almost eliminate the fluctuation of the content of electron emissive material and thereby to improve reliability by forming a hole-sealing layer in the predetermined thickness on the back face of an impregnated cathode body by mechanical working or PVD method and thereafter interposing a soldering material layer. CONSTITUTION:A hole-sealing layer 16 is formed in the predetermined thickness on the back face of a porous impregnated cathode body 11. Said hole-sealing layer 16 plugs a hole part 11b at the opposite side face of the electron emissive face of the cathode body 11 and thereby prevents electron emissive material from diffusing to the back face. And a layer composed of soldering material 15 is interposed between the sealing layer 16 and filler 14 including a heater 13 therein. Next, the sleeve 12 of the outer side of a case filled with the filler 14 is fixed at the periphery of the cathode body 11. Thus, the layer of the soldering material 15 eliminates the fluctuation of the content of the electron emissive material and at the same time, improves the reliability of the cathode body 11.</p> |
