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:
Nov. 28, 1989
Filed:
Dec. 28, 1988
Satoru Anzai, Zama, JP;
Hiroshi Tanaka, Yokohama, JP;
Nikon Corporation, Tokyo, JP;
Abstract
An apparatus for projecting a pattern on a first plane onto a second plane comprises a projection lens system disposed between the first plane and the second plane and including a plurality of lens elements disposed at intervals, a plurality of spaces defined by the plurality of lens elements being formed, and means for isolating at least one of the plurality of spaces from the atmosphere. The at least one space is determined so that the variation in magnification of the projection lens system when the pressure in the at least one space varies with the atmospheric pressure is substantially equal to the variation in magnification of the projection lens system when all of the pressure in the space formed between the first plane and the projection lens system, the pressures in the plurality of spaces of the projection lens system and the pressure in the space formed between the projection lens system and the second plane vary with the atmospheric pressure.