| 摘要 |
Disclosed is a projection optical system having relatively large image-side numerical aperture and projection field and being excellent in mechanical stability in respect of vibrations, and the like. The projection optical system includes a first image-forming optical system for forming a first intermediate image of a first surface (R), a second image-forming optical system having a concave reflective mirror and for forming a second intermediate image based on a radiation beam from the first intermediate image, and a third image-forming optical system for forming a final image on a second surface based on a radiation beam from the second intermediate image. Then, predetermined conditional expressions are satisfied with regard to a clear aperture diameter of the concave reflective mirror, a distance (L) between the first surface and the second surface, and a distance (H) between the concave reflective mirror and a reference optical axis.
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