Broad spectrum ultraviolet catadioptric imaging system
January 15, 2018. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent References 3748015 Monocentric optical systems Catadioptric telescopes Optical relay system with magnification Intense laser irradiation using reflective optics Contact-free measuring apparatus having an F-theta-corrected, catadioptric objective and method for using the same Method and apparatus for detecting defects in repeated microminiature patterns Catadioptric imaging system Method for non-destructive identification for electronic inhomogeneities in semiconductor layers Optical system with two subsystems separately correcting odd aberrations and together correcting even aberrations InventorsAssigneeApplicationNo. 007561 filed on 01/15/1998US Classes:359/357, Having four or more components359/355, Lens, lens system or component359/364With curved reflective imaging elementExaminersPrimary: Henry, Jon W.Attorney, Agent or FirmForeign Patent References
International ClassesG02B 013/14G02B 017/00 G02B 001/00 G02B 021/16 AbstractAn ultraviolet (UV) catadioptric imaging system, with broad spectrum correction of primary and residual, longitudinal and lateral, chromatic aberrations for wavelengths extending into the deep UV (as short as about 0.16 μm), comprises a focusing lens group with multiple lens elements that provide high levels of correction of both image aberrations and chromatic variation of aberrations over a selected wavelength band, a field lens group formed from lens elements with at least two different refractive materials, such as silica and a fluoride glass, and a catadioptric group including a concave reflective surface providing most of the focusing power of the system and a thick lens providing primary color correction in combination with the focusing lens group. The field lens group is located near the intermediate image provided by the focusing lens group and functions to correct the residual chromatic aberrations. The system is characterized by a high numerical aperture (type. greater than 0.7) and a large flat field (with a size on the order of 0.5 mm). The broad band color correction allows a wide range of possible UV imaging applications at multiple wavelengths.Other References
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