Patent ID: 6781766
Filing Date: 2004-08-24
Classification: G02B

Abstract:
A projection optical system for projection exposure which forms an image of a first surface onto a second surface, the projection optical system comprising:a first lens group with positive power which is arranged in an optical path between the first surface and the second surface; a second lens group with negative power which is arranged in an optical path between the first lens group and the second surface; a third lens group with positive power which is arranged in an optical path between the second lens group and the second surface; a fourth lens group with negative power which is arranged in an optical path between the third lens group and the second surface; and a fifth lens group with positive power which is arranged in an optical path between the fourth lens group and the second surface; wherein at least one lens group among the first, second, and third lens groups has an aspherical surface, wherein the first lens group has at least two positive lenses, the second lens group has at least two negative lenses, the third lens group has at least three positive lenses, and the fourth lens group has at least two negative lenses, and wherein the fifth lens group has at least six positive lenses.