| 摘要 |
PURPOSE:To accurately and easily align the direction of the electron rays that are incident on a lens to the optical axis of the lens by providing a deflection means that freely varies the incidence angle of the electron rays while the irradiation area is being fixed and a means that supplies step-type deflection signals to a deflection means. CONSTITUTION:Deflection coils 6x and 7x are kept so that the deflection direction to electron rays can be inverse reciprocally and the ratio of a deflection angle can be fixed and are adjusted so that the electron ray irradiation point on a sample 1 cannot be moved. The output of a pulse rectangular wave generation circuit 11 that outputs a rectangular wave with the wave height value + or -DELTAl is applied to an addition circuit 8 through a switch 10. The electron microscope picture of a square hole can be focused almost at the center of a phosphor plate and the switch 10 is turned on by slightly defocusing an objective lens 3. When the output I0 value of a deflection power supply 9 is adjusted so that the oscillation lengths d1 and d2 of a picture on the phosphor plate can be equaled and the switch 10 is turned off, the incident direction of the electron rays and the optical axis of a lens can accurately be aligned for the X-axis direction. The same way applies also to the Y-axis direction. |
