| 摘要 |
<p>PURPOSE:To make it possible to emit electron beams with a high brightness and a wide projection angle for a long time, by making the angle of the top of an LaB6 cathode as obtuse as possible, while forming an acute angle point at the top to produce discharge readily. CONSTITUTION:The electron optical system of an electron-ray image drawing device of a variable beam-adjusting type is composed of an electron-ray source 1 loaded with an LaB6 cathode, a beam adjuster 2, an electron beam contractor 3, a focusing deflector 4, and a picture screen 5. Electron beam emitted from the LaB6 cathode 6 are once focused at a Wehnelt electrode 7 forming a crossover point 8, accelerated by an anode 9, and emitted to the sample. In this case, the cylindrical chip is given a curvature radius of 200-500mum at the top form point. In such a structure, stable electron beams essential to the electron-ray image drawing device of a variable beam-adjusting type can be obtained.</p> |
