| 摘要 |
PURPOSE:To detect directly the movement of a movable part by providing a detecting means for movable part to an actuator to detect two-dimensionally the change of the movable part on a substrate. CONSTITUTION:A position detecting means 24 for movable part is provided with a light source 21, a mask plate 22 and a split type photodetector 23. The illumination light 41 given from the source 21 is made incident on the detector 23 through an opening 25. When the position of a movable part 16 is set at an original point, the light 41 is set previously so as to irradiate evenly the element detectors 23a-23d of the detector 24. When the part 16 is moved, the opening 25 is also moved. At the same time, the light 41 moves on the detector 23. That is, the irradiating position on the detector 23 moves in the upper and lower directions 41' and 41' with vertical movement of the part 16 and in the right and left directions with rotation of the part 16 respectively. Thus it is possible to know the amounts of displacement of the part 16 in both the vertical and revolving directions by giving the operation to the photodetecting quantity of detectors 23a-23d respectively.
|
