| 摘要 |
PROBLEM TO BE SOLVED: To perform focusing with high accuracy indepently of the surface shape of a specimen. SOLUTION: In this automatic focusing device for microscope, a double slit mask 12 is arranged on an optical axis from a lamp 10 and a single slit mask 16 is arranged on an optical axis from a lamp 14, so that a sighting double beam and a sighting single beam are formed. The sighting double beam and the sighting single beam are made incident and reflected ahead of a ridge by a prism 18. The sighting double beam and the sighting single beam reflected by the prism 18 are formed into an image by a projection lens 20 and the images of the sighting double beam and the sighting single beam are projected to the observed specimen. An image detecting element 40 is disposed at the image-formation position of both sighting beams facing an objective lens 34 through a half mirror 26, and a decision circuit 42 decides symmetry between the sighting double beam and the interposed sighting single beam detected by the element 40 and drives a driving mechanism 48 through a driving circuit 46 in accordance with the decision so as to move a placing stage 50 up and down. |
