| 摘要 |
PURPOSE:To obtain an electron lens of axially asymmetry, by forming protrusive and hollowed parts engageable to each other in end parts at a face-to-face position of cylindrical electrodes constituting the electron lens. CONSTITUTION:In case of using three cylindrical electrodes, protrusive parts 6, 7 and hollowed parts 8, 9 are provided in oppositely facing parts respectively between the first electrode 1 and the second electrode 2 and the second electrode 2 and the third electrode 3. Said protrusive parts 6, 7 and hollowed parts 8, 9 can from axially asymmetrical potential distribution in the vicinity of the oppositely facing parts and hole parts of the electrodes constituting an electron lens to present an axially asymmetrical electron lens havIng performance of tetrode lens. When UPF operating said electron lens, the first electrode 1 and the third electrode 3 are connected to be of the same potential, then slightly higher potential of the intermediate electrode 2 than said potential operates the lens as a diverging lens in an X-Z plane and a focusing lens in a Y-Z plane, while slightly lower potential of the intermediate electrode 2 operates the lens to display opposite quality. |
