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:
Jun. 28, 2005
Filed:
Dec. 28, 2001
Koji Shigematsu, Kawasaki, JP;
Masayuki Mizusawa, Kumagaya, JP;
Youhei Fujishima, Ageo, JP;
Miho Matsumoto, Tokyo-to, JP;
Koji Shigematsu, Kawasaki, JP;
Masayuki Mizusawa, Kumagaya, JP;
Youhei Fujishima, Ageo, JP;
Miho Matsumoto, Tokyo-to, JP;
Nikon Corporation, Tokyo, JP;
Abstract
A projection optical system that projects an image on a first side onto a second plane through a plurality of lenses includes the following elements in order from the first side to the second plane: a first lens group that has a negative refractive power, a second lens group that has a positive refractive power, a third lens group that has a negative refractive power, a fourth lens group that has an aperture stop in the optical path, and a fifth lens group that has a positive refractive power. A clear aperture of a lens surface or an outer diameter of a lens in the projection optical system has a relative maximum in the second lens group, a relative minimum in the third lens group, and a relative maximum in the third-fifth lens groups, and has only one significant minimum between the first side and the second plane.