| 摘要 |
PURPOSE:To determine an accurate multiplying factor by detecting the quantity of an electron beam on a phosphor plate and calculating the multiplying factor based on the detected data for display. CONSTITUTION:After a specimen illumination condition is set and fixed at a desired status, a condenser lens system is set at a proper multiplying factor in a normal control method. Next, a coefficient setting knob provided in a calculating circuit 12 is manipulated so that the multiplying factor value indicated on a display unit 13 equals to that already know. Then, the condenser lens system is controlled optionally. When the image multiplying factor on a phosphor plate 7 is varied by this control and the quantity of an electron beam is changed, a correct multiplying factor value is calculated by a calculating circuit 12, and is indicated on the display unit 13. |
