| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an electron gun suitable for that applied to an electron beam reduction transfer device and capable of obtaining a high emittance and low brightness characteristic at a low current. SOLUTION: At a peripheral part of an electron emission surface 3a of an LaB6 made cathode 3, a film (carbon film 4) is provided which is composed of a conductive substance having a higher work function than a base material of the cathode 3, and the electron emission from the peripheral part of the cathode 3 is controlled as much as possible. A diameter of the electron emission surface 3a is made smaller than that of a Wehnelt hole 2c and a diameter of the base material of the cathode 3 is made larger than that of the hole 2c.</p> |
