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:
Jul. 31, 1990
Filed:
Mar. 07, 1989
John Pastrone, Los Gatos, CA (US);
George H Fellingham, San Jose, CA (US);
Michael Lawless, Boulder Creek, CA (US);
Abbott Laboratories, Abbott Park, IL (US);
Abstract
An ultrasonic sound generator and receiver are spaced apart from each other so as to receive a projecting portion of a cassette in which a liquid carrying passage is defined by a flexible membrane. The liquid carrying passage in the projecting portion fits between the ultrasonic sound generator and receiver, with opposite sides of the flexible membrane in contact with the sound generator and sound receiver. The sound generator and sound receiver each comprise a substrate having a layer of conducting material. Two electrically isolated regions are defined on the conductive layer, and a piezoelectric chip is electrically connected between the two regions. An electrical signal applied between the first and second regions excites the piezoelectric chip on the sound generator, causing it to generate an ultrasonic signal, which is transmitted through the liquid carrying passage. If liquid is present in the passage, the amplitude of the ultrasonic sound signal received by the piezoelectric chip on the sound receiver is substantially greater than when liquid is absent in the passage. The ultrasonic detector thus produces a signal indicative of liquid in the liquid carrying passage.