US Patent 7710640 Projection objective of a microlithographic projection exposure apparatus

A projection objective for a microlithographic projection exposure apparatus. The projection objective can project an image of a mask that can be set in position in an object plane onto a light-sensitive coating layer that can be set in position in an image plane. The projection objective can be designed to operate in an immersion mode, and it can produce at least one intermediate image. The projection objective can include an optical subsystem on the image-plane side which projects the intermediate image into the image plane with an image-plane-side projection ratio having an absolute value of at least 0.3.