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:
Dec. 10, 1991
Filed:
Feb. 08, 1991
Mark E Schafer, Norristown, PA (US);
Timothy L Kraynak, Hatboro, PA (US);
Sonic Technologies, Horsham, PA (US);
Abstract
The present invention relates to a hydrophone specifically designed for use in high pressure shock wave fields, comprising a thin piezoelectric polymer film secured to a rigid hoop structure, having a centrally located active element and two conducting leads extending from the active element on each side of the film. Under the action of high pressure shock waves, the conductive material which makes up the active area electrode and the conductive leads is slowly removed, altering the hydrophone's sensitivity and eventually rendering it unusable. The present invention provides an improved design for a hydrophone which monitors the loss of electrode and lead integrity due to shock wave action so that the hydrophone may be replaced before it produces invalid readings. The leads on each side of the centrally located active element are electrically switched to measure the resistance between the leads and the central portion. In another embodiment, the film may be a disposable item allowing for rapid replacement once damaged.