| 摘要 |
PURPOSE:To correct completely the drift of a sample by detecting the magnitude and direction of the drift of the sample and then by deflecting electron beams on the basis of the detection signal so as to let an electron-beam spot follow up the drift. CONSTITUTION:Time and coordinate signals obtained by light pen 18 are supplied to arithmetic and memory unit 19 to find the magnitude and direction of the drift of a sample. Arithmetic and memory unit 19 memorizes the magnitude and direction of the drift per unit time and then supplies them to controller 13. Controller 13 supplies electeic signals, corresponding to the magnitude and direction of the drift, to deflectors 7x and 7y by way of D-A converters 14x and 14y. Electron beam 2 radiated from electron gun 1 and that of a cathode ray tube are deflected by deflectors 7x and 7y corresponding to the magnitude and direction of the drift. |
