Method and apparatus for aligning target object

摘要

In an optical device having an objective lens for magnifying an image of a target object and a focusing unit including a laser source for irradiating the target object through the objective lens and a focus detecting light-receiving section for receiving light reflected from the target object, positions in the periphery of the target object are detected by using the laser beam emitted from the laser source of the focusing unit while changing a relative positional relationship between the target object and the objective lens.