Method for evaluating a measured parameter

US7728984B2 · kind B2 · utility

Assignee

• INFICON AG · LI

Inventors

• Peter Waegli · Bremgarten, CH
• Felix Mullis · Flums, CH

Key dates

• Filing date: Mar 24, 2008
• Grant date: Jun 1, 2010
• Expiry date: Aug 1, 2028

Classification

• Technology area (CPC G): Physics
• CPC primary: G01B2290/25
• WIPO field: Measurement
• WIPO sector: Instruments

Abstract

For evaluation of a measured parameter with a measuring cell having a cavity which generates for light an optical path length difference changing corresponding to the variation of the measured parameter, the method includes: introducing light from a white light source with the aid of an optical waveguide via a coupler (3) disposed in the path of the optical waveguide into the cavity, coupling out at least a portion of the light reflected back into the optical waveguide from the cavity with the aid of the coupler and conducting this reflected light to an optical spectrometer, determining the optical spectrum of the reflected light in the spectrometer and generating a spectrometer signal, conducting the spectrometer signal to a computing unit, wherein the spectrometer signal is directly converted through the computing unit to an interferogram and from its intensity progression the location of the particular extremal amplitude value is determined and this particular location represents directly the particular value of the optical path length difference in the cavity, which comprises the measured parameter.