| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical position measuring device having two intersecting reference scales and capable of adding a scanning distance between the two reference scales to execute measurement. <P>SOLUTION: The scanning bar is extending in a first or a second direction of two directions X and Y while a scale is extending in the other direction and is offset from the scanning bar by a scanning distance d in a third direction Z perpendicular to the first and the second directions. The divice has a light source LQ, whose light passes through the scanning bar A at an intersection of the scanning bar A and scale M, falls on the scale M, and returns toward the scanning bar A to reach a detector. At the detector, the light is divided into different partial beams by diffraction at optically effective structures of the scanning bar A and the scale M and combined again. A periodic signal is obtained in the detector in response to a shift between the scanning bar A and scale M in the first direction X due to interference of combined partial beams, and a change in the scanning distance d between the scanning bar A and scale M. <P>COPYRIGHT: (C)2012,JPO&INPIT |
