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:
Oct. 14, 2003
Filed:
Sep. 01, 2000
Shinya Satou, Hitachi, JP;
Keiji Hanzawa, Mito, JP;
Satoshi Shimada, Hitachi, JP;
Naohiro Monma, Hitachi, JP;
Atsushi Miyazaki, Mito, JP;
Other;
Abstract
An S/N ratio of an output of a semiconductor pressure sensor is improved, the sensor being of an electrostatic capacitance type pressure sensor for generating an output based upon a ratio between capacitances of a pressure sensitive capacitance element and a reference capacitance element. This semiconductor pressure sensor has: a pressure sensitive capacitance element having an electrostatic capacitance Cs changing with a pressure to be detected; a reference capacitance element having an electrostatic capacitance Cr not changing with the pressure; and a unit for detecting the pressure by outputting a signal corresponding to a ratio between the capacitances Cs and Cr, wherein an initial value Cr of the capacitance Cr and an initial value Cs of the capacitance Cs are defined by 1.2<Cr /Cs <1.8. The Cr /Cs ratio is adjusted by changing the electrode area or the like of both the elements. In this manner, it is possible to obtain a large pressure gauge output &Dgr;V, lower an amplification factor of the amplifier, and provide a high precision of the sensor.