Patent ID: 7701640

Claim:
An immersion optical system that projects an image of an object onto an image plane, the immersion optical system comprising: a plurality of lenses disposed along a light beam path of the immersion optical system; a first dioptric imaging optical system including a part of the plurality of lenses disposed along an optical axis; and a second dioptric imaging optical system including another part of the plurality of lenses disposed along an optical axis, wherein the plurality of lenses include a liquid immerged lens which is contactable with a liquid layer, an intermediate image of the object is formed at an optically conjugate point in the light beam path of the immersion optical system, the optically conjugate point is disposed in an optical path between the first dioptric imaging optical system and the second dioptric imaging optical system, the optical axis of the first dioptric imaging optical system is aligned with the optical axis of the second dioptric imaging optical system, the first dioptric imaging optical system comprises a first negative lens group, a first positive lens group arranged in an optical path between another optically conjugate point and the first negative lens group, and a second positive lens group arranged in an optical path between the first negative lens group and the optically conjugate point, and the second dioptric imaging optical system comprises a second negative lens group, a third positive lens group arranged in an optical path between the optically conjugate point and the second negative lens group, and a fourth positive lens group arranged in an optical path between the second negative lens group and the object surface.