Patent ID: 6891683
Filing Date: 2005-05-10
Classification: G02B,G03F

Abstract:
1. A refractive projection objective for use in microlithography, comprising a lens arrangement with a system diaphragm, wherein the lens arrangement consists of lenses made exclusively of one and the same material, wherein the objective has an optical axis, an object field, an image field, and an image-side numerical aperture larger than 0.7, wherein a light bundle propagating through the objective is defined by said image field and said image-side numerical aperture and has within the objective a variable light-bundle diameter smaller than or equal to a maximum light-bundle diameter, and wherein in a length interval measured on the optical axis from the system diaphragm towards the object field and at least equaling said maximum light-bundle diameter, said variable light-bundle diameter exceeds 85% of said maximum light-bundle diameter.