| 摘要 |
PURPOSE:To shorten the time for detecting a focusing point by estimating variance in a lot from the picture signal of a focused sample in the lot of the sample, and setting the prescribed scanning range of the lot from this estimated variance. CONSTITUTION:A system control part 10 controls the whole including an automatic focusing device 7 and a picture processor 9, etc. A point where the output signal of the device 7 becomes maximum is found out while moving the position of an object lens 41, and is made the focusing point. In the detection of the focal position of the device 7, there are some variance. Therefore, the control part 10 obtains the focal position data by scanning the range in which this variance of the whole lot is considered only about the focal position data of early some samples in the lot. The variance in the lot is estimated from the position data of this focusing point, and the sample is scanned within this range of the variation of the lot. Thus, since the scanning range can be changed or narrowed, the time for detecting the focusing point can be shortened. |
