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:
Sep. 10, 2013
Filed:
Jun. 19, 2008
Petri Välisuo, Vaasa, FI;
Juhani Virtanen, Tampere, FI;
Kari Kymäläinen, Tampere, FI;
Laurentiu Barna, Tampere, FI;
Jarkko Mäkiranta, Siuro, FI;
Petri Välisuo, Vaasa, FI;
Juhani Virtanen, Tampere, FI;
Kari Kymäläinen, Tampere, FI;
Laurentiu Barna, Tampere, FI;
Jarkko Mäkiranta, Siuro, FI;
Marimils Oy, Vantaa, FI;
Abstract
Proximity of a person causes a change in a capacitance value of a sensor capacitor having a pair of capacitive plates. The change is detected by charging the sensor capacitor by coupling the sensor to a voltage supply. The supply is disconnected from a tank capacitor during the charging. The charge is transferred from the sensor capacitor to a tank capacitor. The supply is disconnected from the tank capacitor during the charge transfer. The charging and charge transfer are repeated several times. The voltage of the tank capacitor is monitored. At least one value is determined which depends on the rate of change of the voltage of the tank capacitor. The capacitance of the tank capacitor may be several orders of magnitude higher than the capacitance of the sensor capacitor. The large tank capacitor acts as a part of a low-pass filter which effectively filters out signal noise.