| 摘要 |
PURPOSE:To make it possible to adjust the focus of an automatic microscope means quickly and highly accurately, by changing the distance between the objective lens of an optical system and a surface to be inspected step by step, and selecting the obtained detected signal having the sharpest waveform. CONSTITUTION:An objective lens 2a is placed at a position (base point) where focusing is approximately obtained. Then, the lens 2a is lowered by 1mum and scanned in the direction of an arrow G. The signal waveform of a CCD detector 3 is stored 8. Then, a microscope means 2 is lifted by a driving part 9 step by step by 0.05mum. The same operation is repeated. When the position of the lens 2a becomes higher than a specified position by 2mum, the operation is once stopped. Siad position is lower then the base point by 1mum. At this time, about 40 detected waveforms are stored in a control part 8. The waveform showing the sharpest peak is selected by operations such as differentiation of the detected waveforms and the like. Thus the focus adjustment of the automatic microscope means 2 can be carried out at the accuracy of 0.05mum quickly. |
