Linear encoder

摘要

A linear encoder includes a plate-type scale and a head which moves along the longitudinal direction of the scale. The scale has graduations formed on a surface of the scale and arranged along the longitudinal direction of the scale. The head includes a reading part which detects an amount of a relative movement of the head with respect to the scale by reading graduations formed on the scale. The head includes four bearings each having a rotation axis extending along the transverse direction of the scale. Each of the bearings is situated on the head so as to abut against a surface of the scale, to function as a spacer to maintain a distance between the scale and the head. The scale acts as a plate member interposed between the reading part and the graduations.