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:
Jun. 20, 2000
Filed:
Apr. 07, 1998
Takeshi Matsubara, Tokyo, JP;
Yujiro Kitaide, Tokyo, JP;
Fuji Electric Co., Ltd., Kawasaki, JP;
Abstract
A pressure in a pressurizing chamber of a micromachine apparatus for transferring a fluid is measured inexpensively under an actual-use or a similar condition. A piezoelectric element used as an actuator for applying a pressure to the fluid in the pressurizing chamber is also used as a pressure sensor. A charge amplifier is used to measure the amount of charge Q.sub.1 applied to an electrode of the piezoelectric element when the piezoelectric element is driven while the pressurizing chamber filled with the fluid, and the amount of charges Q.sub.2 when the piezoelectric element is driven while the chamber contains no fluid. The obtained signals are inputted to a storage and operation processing device to determine (Q.sub.1 -Q.sub.2) to determine the pressure of the fluid in the pressurizing chamber. The piezoelectric element or capacitor for the purposes of comparison can be used to simultaneously measure Q.sub.1 and Q.sub.2.