PURPOSE: To provide a projection optical system having a large exposure region, high resolving power and a large numerical aperture and a projection aligner provided with the same.
CONSTITUTION: The projection optical system PL projects the image of a first object R on a second object W with a constant reduction ratio. The projection optical system PL is provided, in order from the side of the first object R, with a first lens group having a positive refractive power, a second lens group composed of substantially afocal system and a third lens group having a positive refractive power. By representing the focal distance of a whole system by F, the projection magnification of the projection optical system by B, distance between the first object R and the second object W by L, distance between the intersection of the extending line of a light beam on the side of the first object when the light beam from the projection optical system PL of the second object side goes out from the projection optical system PL and the first object surface by (e) and the height of a light beam of the first object from the optical axis of the projection optical system PL when the light beam passed through the projection optical system PL reaches the first object R by (h), the conditions: 1.8≤F/(B.L) and h/e≤3/1000 are satisfied.
USHIDA KAZUO
SUENAGA YUTAKA
ROMEO AI MERUKADO
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