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:
Oct. 14, 2003
Filed:
Dec. 10, 2001
Yutaka Suenaga, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A projection optical system according to the present invention whose image side numerical aperture is greater than or equal to 0.75, and which forms an image of a first object upon a second object using light of a predetermined wavelength less than or equal to 300 nm, comprises: a first lens group G of positive refractive power; a second lens group G of negative refractive power; a third lens group G of positive refractive power; and a fourth lens group G of positive refractive power, and: the first lens group G the second lens group G the third lens group G and the fourth lens group G are arranged in order from a side of the first object; and a distance D in mm along an optical axis between an optical surface of the fourth lens group G closest to the second object, and the second object, satisfies a condition of 0.1<D<5.