| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical device advantageous in reducing both stray light and a required space.SOLUTION: The optical device, for detecting a mark image on a substrate, includes an optical system that forms the mark image, a detector that detects the image, an iris that is disposed on the optical system and has apertures corresponding to a first field of view and a second field of view of the detector, a light shielding member, and a drive mechanism that positions the light shielding member so as to enable one of the first field of view and the second field of view and disable a part of the other one. |
