| 摘要 |
PURPOSE:To enable the correction of the longitudinal direction of an elongated electron beam to random direction, by rotary adjusting the mounting position of a ferro-magnetic chip around the tube axis. CONSTITUTION:The electron emitted from the cathode will form an elongated cross-over by means of a rotary asymmetric pre-focus lens comprising the first grid 52 having an elongated opening, the second grid 53 having a circular opening and the third grid 54, then said cross-over is focused onto a fluorescent face through a field main lens provided by a rotary symmetric field 81 which is produced by permanent magnet 6 located at the outer-circumference of a neck tube. Then a ferro- magnetic chip 7 is properly rotated to direct the longitudinal direction of the elongated beam spot toward desired direction. |
