| 摘要 |
PURPOSE:To realize a clear detection with a simple structure by placing a reflector and a light transmitting plate in a gap between plural substrates placed on a substrate holder, and using reflected light for detecting a synchronizing signal. CONSTITUTION:Monochromatic light for monitoring an optical interference, projected from a laser light source 1 is reflected by mirrors 41, 42- provided between plural substrates 51, 52- on a substrate holder 55 rotating around a shaft 10, and reaches a synchronizing signal detecting sensor 64. An optical path reaching a regular optical interference monitoring sensor 6 is path of measuring light reflected by the surface of the substrate 51, etc. |
