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:
Aug. 14, 2007
Filed:
Apr. 25, 2002
Thomas L. Andrade, Los Gatos, CA (US);
Thomas L. Andrade, Los Gatos, CA (US);
Atrua Technologies, Inc., Campbell, CA (US);
Abstract
A capacitance sensor system and method includes a capacitive sensor as an array of sensor electrodes near the surface of the integrated circuit and charge pump circuits for measuring the capacitance at each sensor electrode. Shield electrodes and unused sense electrodes are used for background capacitance cancellation at each array location. The shield electrodes are switched between the circuit supply potentials in a manner synchronous to the capacitance sensing at the sense electrodes. The improved background capacitance cancellation allows all circuitry to be located outside the sensor array. The capacitance data is used to determine the positions of fingerprint artifacts and other fingerprint features.