| 摘要 |
PURPOSE:To enable measurement of two-dimensional and rotating displacements without contact with a target by detecting the extent of the movement of a speckle with photodetectors placed in the position deviated forward and backward from the imaging position of the target and calculating the same. CONSTITUTION:Photodetectors 71, 74 and photodetectors 72, 75 are disposed respectively before and behind an imaging position P and therefore the detectors generate the outputs in the directions opposite from each other with respect to the rotation of a target 4. If the outputs from the photodetectors 71, 74, 72, 75 are designated to be respectively Sx1, Sx2, Sy1, Sy2, Sx1+Sx2 is the displacement in the X-axis direction, Sx1-Sx2 is the rotating displacement around the Y-axis, Sy1+Sy2 is the displacement in the Y-axis direction and Sy1-Sy2 is the rotating displacement around the X-axis. The outputs respectively proportional to X, Y, thetax, thetay are thus obtd. |
