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. 04, 2007
Filed:
Jun. 04, 2003
Terence J. Knowles, Barrington, IL (US);
Wayne J. Wehrer, Austin, TX (US);
Chris Kalmus, LaGrange, IL (US);
Charles F. Bremigan, Iii, Jarrell, TX (US);
Terence J. Knowles, Barrington, IL (US);
Wayne J. Wehrer, Austin, TX (US);
Chris Kalmus, LaGrange, IL (US);
Charles F. Bremigan, III, Jarrell, TX (US);
Illinois Tool Works Inc., Glenview, IL (US);
Abstract
A circuit for an acoustic wave switch or sensor having a resonant acoustic wave cavity detects a touch or sensed event using a time domain approach. The circuit includes a controller that drives an acoustic wave transducer to generate a resonant acoustic wave in the acoustic wave cavity during a first portion of a sampling cycle. In a second portion of the sampling cycle, the controller monitors the time that it takes for the acoustic wave signal from the transducer to decay to a predetermined level. Based on the decay time, the controller detects a sensed event, such as a touch on the acoustic wave switch/sensor.