| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic focusing device which performs focus control for the surface of material automatically and performs the focus control with high accuracy. SOLUTION: The automatic focusing device is provided with an illumination diaphragm having an opening, an illumination means that illuminates the surface of the material with illumination light via the illumination diaphragm, a splitting means that splits a luminous flux reflected on the surface of the material by illumination of the illumination light into two luminous fluxes, a photoelectric converting means that receives the two luminous fluxes split by the splitting means and forms two images of the illumination diaphragm corresponding to the two luminous fluxes and a focus control means that detects automatic focusing (AF) error information representing the deviation of a focus on the basis of a relative relationship of the two images of the illumination diaphragm, changes the relative position with the surface of the material in accordance with the AF error information and, thereby, performs the focus control. The automatic focusing device is characterized in that a shaped modulation is applied to the opening of the illumination diaphragm. COPYRIGHT: (C)2004,JPO |
