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:
Apr. 30, 2013
Filed:
Apr. 28, 2010
Thomas Coppe, Orbey, FR;
Jean-luc Henry, Colmar, FR;
Michael Schoening, Juelich, DE;
Buerkert Werke GmbH, Ingelfingen, DE;
Abstract
An analyte concentration, in a sample fluid, is determined by differential measurement. Two or more capacitive field effect sensors have an identical basic structure and are arranged in a shared measuring cell. One of the sensors forms a measuring sensor with an active transductor layer. Another sensor forms a reference sensor without an active transductor layer. The sensors are contacted with the sample fluid and the sensors, have an associated reference electrode, or have a shared reference electrode. A bias voltage composed of an electric DC voltage and a superimposed AC voltage is applied between each sensor and associated reference electrode(s) Capacitance changes due to the analyte are eliminated by controlling the bias voltage applied to the measuring sensor in a closed control loop. A measuring signal is obtained by calculating a difference between voltage values representative of DC voltage potentials applied to the measuring sensor and reference sensor, respectively.