| 摘要 |
PURPOSE: To provide an automatic focus detector for a microscope where automatic focus detecting range is enlarged without hindering observation through a microscope. CONSTITUTION: This automatic focus detector for a microscope is provided with an irradiation optical system irradiating an object surface 6 with light from a light source 1, an image-formation optical system dividing the reflected light from the object surface 6 into two luminous fluxes having the difference of an optical path and forming either luminous flux into an image at a 1st image-formation position (a) and forming the other luminous flux into an image at a 2nd image-formation position (b), respectively, and a photoelectric conversion element 7 arranged between both positions (a) and (b) and receiving two luminous fluxes; and a focusing state is detected by comparing two signals from the conversion element 7. The detector is provided with a plate member 10 arranged at a position conjugate to the object surface 6 and having a low frequency pattern, a pattern illuminating light source 11 illuminating the plate member 10, and an arithmetic part 20 turning on the light source 11 when the focusing state can not be detected. The low frequency pattern is formed on the object surface 6 by turning on the light source 11, so that the focusing state is detected. |
