| 摘要 |
<p>PURPOSE:To make the radius of curvature of the tip in the order of submicron and to prevent the tip of any electron cathode material from being a flat form, by carrying out an electrolytic polishing by sending a pulse-form current when the tip of an electron cathode material selected from a specific material is sharpening-processed in the electrolytic polishing. CONSTITUTION:As a material 1 for an electron cathode, a conductive substance selected from a group of transistion metal carbonates, rare earth element borides, and high melting point metals is used. A pulse-form current whose voltage and length are controlled is delivered between an electron cathode material 1 and a ring-form electrode 2 from a power source 6 through lead wires 4 and 5. The pulse may be either a rectangular pulse or a triangular pulse. As the voltage, a voltage to make the polishing speed equal at all the crystal surfaces is applied ordinarily being 4V or higher. The length of the pulse is selected to be the length not to generate a nonconductor in the crystal surfaces being, less than 0.5sec.</p> |
