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. 26, 1994
Filed:
Mar. 26, 1992
Akira Ishida, Tsuchiura, JP;
Nikon Corporation, Tokyo, JP;
Abstract
Straightness is measured with high accuracy through the use of two laser beams of different wavelengths to thereby eliminate any measurement error due to deflection caused by the turbulence of a medium through which the laser beams propagate. An exemplary apparatus for measuring straightness is characterized in that two laser beams of different wavelengths are received by a position sensor, respective measured values including the amounts of deflection created in the two laser beams are sent to a calculating portion, and in the calculating portion, a calculating process of offsetting the amounts of deflection created in the laser beams from the two measured values is carried out to thereby detect the position of a stage and measure straightness.