| 摘要 |
PURPOSE:To confirm easily under what condition the image is obtained by displaying the disfocus amount indicating the shift of the specimen position from the correct focus position and the phase contrast conversion function of the objective lens through a function signal generating means. CONSTITUTION:The signal relating to the acceleration voltage of the electron beam, the signal indicating the disfocus amount of the specimen 1 position and the correct focus position from a specimen carrying mechanism 3 and the signal indicating the excitation current level of an objective lens 6 from an objective lens excitation operational means 17 are applied respectively on a function signal generating means 19a. Then the signal indicating the phase contrast transmission function of the objective lens 6 is provided to an indicating means 15 to produce a curve 20. While an electrical signal corresponding with the strength of the electron beam irradiating on a phosphor board 8 is provided from an image pick-up tube 11 to a preamplifier 12, while a Fourier conversion signal is provided from a Fourier conversion means 13a to an indicating means 15 thus to display a curve 21. Consequently it can be confirmed easily under what condition the image is obtained. |
