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:
Sep. 12, 2000
Filed:
Nov. 03, 1998
Marc Spinali, San Ramon, CA (US);
Nikon Corporation, Tokyo, JP;
Abstract
A hybrid optical barrel as a projection optical unit includes a plurality of cell groups disposed in series along an optical axis, each cell group including at least a cell unit and each cell unit including a lens and a cell holding the lens. The optical barrel also includes a connecting barrel member carrying the plurality of cell groups, the connecting barrel member being made of a material with a CTE<3.0 ppm.degree.C. such as Invar, Ultra Low Expansion.TM. glass, Zerodur glass, or silicon carbide. The connecting barrel member may comprise a plurality of sub-barrels disposed in series along the optical axis. Alternatively, the connecting barrel member may comprise a plurality of spacing members. Therefore, during an axial displacement of the optical barrel caused by a temperature change, relative axial dimensions of the sub-barrels or the spacing members remain substantially constant, thereby reducing an overall displacement of the lenses within the plurality of cell groups.