FOCAL POSITION DETECTING DEVICE AND METHOD

摘要

PROBLEM TO BE SOLVED: To provide a focal position detecting device and a focal position detecting method for detecting a focal position in optical measurement at high speed. SOLUTION: By consecutively driving a stage 41 in a direction Z, a sample 9 placed on the stage 41 is moved in the direction of the optical axis Lb of an image formation optical system 20b and plural images are acquired during the consecutive movement. The image acquiring operation includes image pickup operation by an image forming part 31 and transfer operation to a memory 32. An evaluated value calculation part 33 calculates the focus evaluated values F of the respective images concurrently with the image acquiring operation, so that total processing time is shortened. A focal position calculation part 60 calculates the focal position based on plural focus evaluated values F.