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:
May. 29, 2001
Filed:
Jan. 26, 1999
Claude Beauducel, Henonville, FR;
Institut Francais du Petrole, Rueil-Malmaison cedex, FR;
Abstract
The invention is an interferential refractometry method and device using fine measurement of the displacement of the fringes of an interference pattern between two light beams with one of the beams undergoing phase variations due to variations in the refractive index thereof. The method comprises application, to one of the two beams, of a relatively fast periodic phase modulation by a modulating signal. Displacement of the fringes resulting from the combined application of the two modulations is picked up by a photodetector and a measuring system evaluates the slow modulation by determining the frequency spectrum of the signal coming from the detect or and measuring the phase shift affecting the fundamental frequency of this frequency spectrum. The method may be applied to detection of variations in the composition of mixtures, for example in analytical or preparative chromatography.