POSITION DETECTION DEVICE

摘要

PROBLEM TO BE SOLVED: To detect an absolute position to restore the origin without a movement operation in a height direction when displacement of a measured surface of a measured member capable of a relative movement in a measurement direction and a vertical direction is detected on the basis of measurement light reflected by the measured surface in an incremental-type displacement detection device.SOLUTION: A position detection device comprises a relative position detection part 20 and an absolute position detection part 30 that optically detect a relative position and an absolute position in a measurement direction Z on the basis of measurement light L1 reflected by a measured surface 1a of a movable measured member 1 in a direction X orthogonal to the measurement direction Z. The position detection device has an absolute position detection area 4 in which an optical axis of the measurement light L1 is moved to an end of a movement direction X of the measured member 1. The absolute position detection part 30 detects an absolute position by moving the optical axis of the measurement light L1 in the absolute position detection area 4, and restores position information obtained by the relative position detection part 20.