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:
Nov. 03, 1992
Filed:
Nov. 30, 1990
Martin J Kenney, Startup, WA (US);
Ultrasonic Arrays, Inc., Woodinville, WA (US);
Abstract
A capacitive transducer including a back plate and a tensioned dielectric diaphragm with a conductive layer is operated as a sonic energy emitter and receiver. The polarity of the dc bias applied to the transducer is periodically reversed to prevent charging and polarization of the dielectric diaphragm due to the applied electrostatic field. The bias voltage polarity is controlled in timed sequence with the application of a fluctuating voltage to generate sonic energy with optimum efficiency. Electrical signals resulting from received sonic energy are selectively inverted and provided with compensation for differences resulting from differences in bias polarities.