DISPOSITIF DE DETECTION DE POSITION

摘要

A position detecting device for detecting the position of an object includes an illumination optical system for producing a light beam and for irradiating the object with the light beam, an optical system for focusing the light beam, a focus position controlling system operative to change the position at which the light beam is focused by the focusing optical system, a first detecting device for receiving the light beam reflected from the object to detect the state of incidence of the light beam on the object, and a second detecting device for detecting the position of the object on the basis of the detection of the state of incidence of the light beam on the object by the first detecting means.