A projection optical system for projecting an image of a first object onto a second object includes a first imaging optical system that forms a first intermediate image of the first object, and includes a lens, a second imaging optical system that forms a second intermediate image of the first object,...http://www.google.se/patents/US20040233405?utm_source=gb-gplus-sharePatent US20040233405 - Projection optical system, exposure apparatus, and device manufacturing method
