Patent ID: 7446952

Claim:
A catadioptric projection objective for imaging an off-axis effective object field arranged in an object surface of the projection objective onto an off-axis effective image field arranged in an image surface of the projection objective comprising: an optical axis; an effective object field situated entirely outside the optical axis and having a length A in a first direction and a width B in a second direction perpendicular to the first direction such that a circular area of minimum size enclosing the effective object field defines a radius R EOF of the effective object field according to: R EOF = ( A / 2 ) 2 + ( B / 2 ) 2 ; a circular design object field centered around the optical axis having a design object field radius R DOF , where the projection objective is essentially corrected with respect to image aberrations in zones having radial coordinates smaller than R DOF and wherein the projection objective is not fully corrected in zones having radial coordinates larger than R DOF , wherein the following conditions are fulfilled: R DOF =γR EOF and 1≦γ≦1.2.