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:
Dec. 22, 1998
Filed:
May. 30, 1997
Masato Hatasawa, Yokohama, JP;
Masatoshi Ikeda, Tokyo, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Four specified lenses 22.sub.1 to 22.sub.4 of a plurality of lenses in a projection optical unit are subjected to special processing (astigmatic surface processing) so that asymmetric component aberration relative to an optical axis is generated. Each of the lenses 22.sub.1 to 22.sub.4 is held by each of secondary lens frames 20 set in each of primary lens frames 14. Each of the secondary lens frames 20 is constructed so that it can be rotated from the outside of a lens barrel 12. The asymmetric component aberration relative to the optical axis of an optical system comprising all lenses for constituting the projection optical unit 10 can be easily corrected by rotating a pair of two of the lenses 22 subjected to the astigmatic surface processing. The projection optical unit is used for a projection exposure apparatus.