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. 04, 2000
Filed:
Aug. 29, 1996
Hitoshi Matsuzawa, Setagaya-ku, JP;
Koji Shigematsu, Kawasaki, JP;
Kazumasa Endo, Kawasaki, JP;
Yutaka Suenaga, Yokohama, JP;
Nikon Corporation, , JP;
Abstract
The present invention relates to an exposure apparatus having a high-performance projection optical system having a relatively large numerical aperture and achieving bitelecentricity and superior correction of aberrations, particularly distortion, in a very wide exposure area. Particularly, the protection optical system according to the present invention is composed of a first lens group G.sub.1 with a positive refracting power, a second lens group G.sub.2 with a negative refracting power, a third lens group G.sub.3 with a positive refracting power, a fourth lens group G.sub.4 with a negative refracting power, and a fifth lens group G.sub.5 with a positive refracting power in order from the side of a first object R. The present invention is directed to finding of suitable ranges of focal lengths for the first to fifth lens groups G.sub.1 -G.sub.5, based on the above arrangement.