Patent ID: 6964485

Claim:
A collector for guiding light with a wavelength of ≦193 nm onto a plane, said collector comprising: a first mirror shell for receiving a first ring aperture section of said light and irradiating a first planar ring section of said plane with a first irradiance; a second mirror shell for receiving a second ring aperture section of said light and irradiating a second planar ring section of said plane with a second irradiance; and a central aperture obscuration with a numerical aperture≦0.30, wherein said light impinges with an angle of incidence of less than 20° to surface tangents of said first and second mirror shells, wherein said first and second mirror shells are rotationally symmetrical and concentrically arranged around a common axis of rotation, wherein said first and second ring aperture sections do not overlap with one another, wherein said first planar ring section substantially abuts said second planar ring section, wherein said first irradiance is approximately equal to said second irradiance, and wherein said collector has a focal point.