Patent attributes
Rotating polygon mirrors are configured such that angles formed by a rotation axis and mirror surfaces differs from one another in the mirror surfaces in order to shift a collecting point of a scanning light flux in a sub-scanning direction in association with rotation at constant angular speed. A collecting point position forming optical system is configured such that the collecting point is moved in an inspection range Zr in a height direction Z. The XYZ scanning is performed by moving the inspection object in the sub-scanning direction such that the collecting point shifted in the sub-scanning direction and the height direction is linearly scanned in the height direction of the inspection object in synchronization with the rotation of the rotating polygon mirror at the constant angular speed, and the an appearance positional coordinate of the inspection object is determined by a confocal method to perform the appearance inspection.
