| 摘要 |
PURPOSE: To provide an automatic focus detecting method for a microscope by which stable focusing is always realized without erroneously recognizing a focusing position. CONSTITUTION: An optical image formed by an objective lens 3 for observing a sample 2 on a stage 1 is projected to a line image sensor 3, photoelectrically converted and further allowed to pass through an analog signal processing circuit 9 and a contrast arithmetic operation part 10 so as to generate the contrast value of the optical image, while a focusing point is detected by evaluating the contrast value. The stage 1 is moved in a direction where the contrast value rises along the optical axis of the objective lens 3 so as to detect a position where the contrast value suddenly lowers by such movement. In the case of detecting the position where the contrast value suddenly lowers, the stage 1 is moved further within a specified distance so as to detect a position where the contrast value suddenly recovers. In the case of detecting the change of the contrast value at two points, the stage 1 is moved to a central position between the changing points. |
