| 摘要 |
At the time of detecting a position of a shutter plate, a laser light, for instance, is radiated from a detector (an optical sensor). The radiated laser light reaches the shutter plate through a window of a chamber. Then, the laser light is reflected by the surface of the shutter plate and re-enters the detector. The detector detects the time required from the emission of the laser light to the entry of the reflected light. |
