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:
Feb. 27, 2007
Filed:
Sep. 15, 2005
Bert Willing, Blonay, CH;
Markus Kohli, Grandson, CH;
Andreas Seifert, Denens, CH;
IR Microsystems SA, Lausanne, CH;
Abstract
The gas detector device comprises at least a VCSEL source and at least a light sensor for detecting a light beam having passed through a sample chamber containing a given gas to be detected. The detection signal of the sensor directly provided to or is time derivated by an electronic derivator and then provided to respective lock-in amplifiers in order to generate a two different 2f-detection, f being the frequency of a wavelength modulation of the source, and thus to provide two corresponding measuring signals the division of which gives a precise value of the gas concentration. The invention uses at least a first modulation reference signal at twice and a second modulation reference signal at twice of the modulation frequency of the laser source. Providing at least a first 2f modulation reference signal has advantages over the prior art, because by using such a reference modulation signal it is possible measure the absolute intensity and therefore to receive the same result at different temperatures or at mode hopping of the laser. A further advantage is that the measurement accuracy is independent from the gas concentration.