| 摘要 |
PURPOSE:To surely control a position even for an object having plural reflecting films by allowing a reflected light coinciding with a reflecting surface instructing signal, to be made incident on a photoelectric converter, and also, allowing a detecting signal obtained in a horizontal moving point to coincide with a detecting signal stored in the next point. CONSTITUTION:When a reflecting surface instructing signal for designating a reflecting surface which is used as an object, from among plural reflecting surfaces 5A, etc. formed by an object 5 is set, a detecting signal S2 and S13 and the reflecting surface instructing signal are compared, and the object 5 is brought to a position control so that a reflected light from the reflecting surface coinciding with the reflecting surface instructing signal is made incident on a photoelectric converter 9. Also, at the time of controlling a focal position with regard to plural points on the reflecting surface 5A, etc. of the object 5, the detecting signal S13 which is used for a position control with regard to a first point among plural points is used as a detecting signal S16, and the object 5 is brought to a position control so that the detecting signal S13 obtained with regard to a second point coincides with the stored detecting signal S16, when the object 5 moves horizontally and a position in which a detecting light is radiated to the object 5 moves horizontally from the first point to the second point.
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