The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 25, 2011
Filed:
Oct. 06, 2005
Karl Heinz Schuster, Koenigsbronn, DE;
Karl Heinz Schuster, Koenigsbronn, DE;
Carl Zeiss SMT GmbH, Oberkochen, DE;
Abstract
An aspheric reduction objective has a catadioptric partial objective (L), an intermediate image (IMI) and a refractive partial objective (L). The catadioptric partial objective has an assembly centered to the optical axis and this assembly includes two mutually facing concave mirrors (MM). The cutouts in the mirrors (BB) lead to an aperture obscuration which can be held to be very small by utilizing lenses close to the mirrors and having a high negative refractive power and aspheric lens surfaces (). The position of the entry and exit pupils can be corrected with aspherical lens surfaces () in the field lens groups. The number of spherical lenses in the refractive partial objective can be reduced with aspherical lens surfaces () arranged symmetrically to the diaphragm plane. Neighboring aspheric lens surfaces () form additional correction possibilities.