Patent ID: 7030965

Claim:
A catadioptric system comprising: a first image forming optical system including, at least, a first reflecting mirror and a second reflecting mirror with the first reflecting mirror set further toward a first plane, in which light from the first plane travels around an outside of the first reflecting mirror and is incident to the second reflecting mirror, light reflected at the second reflecting mirror is incident to the first reflecting mirror and, after light is reflected at the first reflecting minor, light travels around an outside of the second reflecting mirror so as to form a first intermediate image of the first plane; a second image forming optical system including, at least, a third reflecting mirror and a fourth reflecting minor with the third reflecting mirror set further toward the first plane, in which light having traveled via the first image forming optical system travels around an outside of the third reflecting mirror and is incident to the fourth reflecting mirror, light reflected at the fourth reflecting mirror is incident to the third reflecting mirror and, after light is reflected at the third reflecting mirror, light travels around an outside of the fourth reflecting mirror so as to form a second intermediate image of the first plane; and a refractive type of third image forming optical system that forms a final image of the first plane onto a second plane with light having traveled via the second image forming optical system, wherein: optical members constituting the first image forming optical system, the second image forming optical system and the third image forming optical system are all disposed along a single linear optical axis.