| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic focusing device which performs follow up focusing operation while transferring an observation object and a processing object, preliminarily restricts distance between an objective lens and the objects within a certain range, shortens distance for performing the final focusing operation after standstill to shorten focal time. SOLUTION: The automatic focusing device has a projection means 30A for projecting two pin holes 7A, 7B with different distance in the optical axis direction and in the direction perpendicular to the optical axis direction on a flat surface of an object 1 to be measured via an objective lens 2 and an operation means 11 for calculating difference between focal positions of projected images on the side of the object to be measured based on level difference of the two pin holes 7A, 7B and magnification of the objective lens 2. COPYRIGHT: (C)2006,JPO&NCIPI |
