| 摘要 |
PROBLEM TO BE SOLVED: To provide high focusing accuracy even to objective lenses from an extremely low magnification to a high magnification while preventing the enlargement of the entire device and cost rise and to provide a further highly reliable automatic focusing device for a microscope. SOLUTION: This automatic focusing device is loaded on the microscope provided with the objective lens 7 switchable to an optional magnification including the extremely low magnification and a three-dimensionally movable scanning stage 1 for loading a sample. In this case, when the objective lens of the extremely low magnification is mounted and focusing onto the sample can not be attained the observation part of the sample is stored as the coordinate of a stage plane, the scanning stage 1 is moved within an optional range by stage driving parts 14 and 15 so that focusing is performed at a position capable of obtaining the level of a luminous flux equal to or more than a prescribed threshold level, and then the observation part is restored thereto. |
