| 摘要 |
PURPOSE:To correct the inclination of a sample to focus the sample in the visual field even when the sample is inclined by driving three Z shafts so that respective patterns arranged on a projection pattern at intervals of a specific angle are focused. CONSTITUTION:A projection pattern 11 is provided which has three patterns equally arranged on a concentric circle at intervals of 120 deg. and is irradiated by a light source 10. Z shafts 21 to 23 corresponding to three patterns 31 to 33 of the projection pattern 11 on a sample 1, Z shaft drivers 20, and peak hold driving circuits 17 to 19 which drive Z shafts so that outputs of photoelectric transducers 14 to 16 have peaks are provided. Z shafts 21 to 23 are driven by peak hold driving circuits 17 to 19 and drivers 20 to focus patterns 31 to 33 on the projection pattern 11. Thus, the whole of the sample surface is focused though the sample surface and the optical axis of an objective lens are inclined to each other. |
