| 摘要 |
A displacement detection apparatus includes a scale unit and a detection head unit. The scale unit has a reference track unit and sub-track units, the pitch directions of these units being different from one another. The detection head unit has three or more detection units configured to read scales of the reference track unit and the sub-track units and to output signals in accordance with the read scales. The three detection units detect displacement in two orthogonal directions on a plane parallel to a plane along which the detection head unit moves. |
