Patent ID: 7428105

Claim:
A system, comprising: a plurality of optical elements arranged along an axis between a first plane and a second plane, the plurality of rigid optical elements comprising a first rigid lens having a concave surface, the first rigid lens being formed from a material having a refractive index n L at a wavelength λ, the system being configured to support a liquid adjacent the concave surface of the first rigid lens between the first rigid lens and the second plane, wherein the system is a microlithography projection objective having a maximum image-side numerical aperture, NA, greater than 1 which during operation is configured to direct radiation at λ from the first plane to the second plane and image an object positioned at the first plane to the second plane when a liquid having a refractive index n F at λ is positioned adjacent the concave surface of the first rigid lens, where n F is greater than n L .