Displacement detecting device, scale calibrating method and scale calibrating program

摘要

A displacement detecting device includes: a scale (10) which has an optical lattice; a detecting unit (20) which is disposed so as to be movable in a scanning direction relative to the scale, inclusive of at least a first detection portion (21), a second detection portion (22) and a third detection portion (23), arranged in the scanning direction for detecting position information from the optical lattice; and a calculating portion (30) configured to obtain a self-calibration curve on graduations of the scale by specifying positions of the detection portions and calculating measurement error based on the position information detected by the detecting unit, wherein: the detecting unit is provided so that a distance between the first detection portion (21) and the second detection portion (22) and a distance between the second detection portion (22) and the third detection portion (23) are different from each other and do not form an integral multiple.