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:
May. 30, 1989
Filed:
Jan. 19, 1988
King W Yeung, Fremont, CA (US);
Douglas L Franz, Vancouver, WA (US);
Hewlett-Packard Company, Palo Alto, CA (US);
Abstract
A drop detector having a piezoelectric membrane mounted to a substrate is presented. When a drop strikes the piezoelectric membrane, the membrane vibrates at a selected resonant frequency. The resonant frequency is selected to enhance the sensitivity of the drop detector and the signal-to-noise ratio of the output. The value of the selected resonant frequency depends on the type of material used for the piezoelectric membrane, the thickness of the membrane, the mounting of the membrane to the substrate, and other parameters such as the coating on the membrane. The vibrations of the membrane produce an output signal having a frequency equal to the selected resonant frequency. Since the frequency of the output signal is known, the output signal can be filtered with a bandpass filter to enhance the signal-to-noise ratio of the output signal. The resulting membrane drop detector is a high sensitivity, high signal-to-noise ratio drop detector.