Patent ID: 6912094
Filing Date: 2005-06-28
Classification: G02B,G03F

Abstract:
1. A projection optical system that projects an image of a first plane onto a second plane via a plurality of lenses, comprising: a first lens group arranged in an optical path between the first plane and the second plane and having a negative refractive power; a second lens group arranged in the optical path between the first lens group and the second plane and having a positive refractive power; a third lens group arranged in the optical path between the second lens group and the second plane; a fourth lens group arranged in the optical path between the third lens group and the second plane; and a fifth lens group arranged in the optical path between the fourth lens group and the second plane and having a positive refractive power; wherein, in a direction from the first plane side toward the second plane, a clear aperture of a lens surface or an outer diameter of a lens in the projection optical system increases in the first lens group, changes from increasing to decreasing in the second lens group, changes from decreasing to increasing in the third lens group, and monotonically decreases in the fifth lens group, and wherein a condition is satisfied, wherein Mx2 is a clear aperture of a lens surface having the largest clear aperture, or outer diameter of a lens having the largest outer diameter, in the second lens group, and Mn3 is a clear aperture of a lens surface having the smallest clear aperture, or an outer diameter of a lens having the smallest outer diameter, in the third lens group, and wherein at least one lens of the plurality of lenses is held such that at least one of a position and an orientation is adjustable, and a numerical aperture of the second plane of the projection optical system is equal to or more than 0.8.