| 主权项 |
1. A Wynn-Dyson imaging system that operates with ultraviolet (UV) light, comprising along an optical axis:
a mirror having a concave surface; an aperture stop located at the mirror that determines a numerical aperture of the system; a lens assembly with positive refracting power and having a front end and a back end, with the lens assembly being arranged adjacent the mirror and spaced apart therefrom with the front end facing the mirror; first and second prisms operably disposed on opposite sides of the optical axis and adjacent the back end of the lens assembly, the first and second prisms having respective first and second planar surfaces, wherein the first and second planar surfaces are arranged adjacent object and image planes, respectively; and at least one of:
a) the first and second prisms each being made of a glass material having a coefficient of thermal expansion of no greater than about 100 ppb/° C.; andb) a first window operably disposed between the planar surface of the first prism and the object plane and that substantially transmits the UV light and that substantially blocks infrared (IR) radiation in a wavelength range from 2 microns to 20 microns, and a second window that is operably disposed between the planar surface of the second prism and the image plane and that substantially transmits the UV light, wherein the first and second windows are configured to maintain imaging symmetry. |
