Fuji Electric Co., Ltd.

Toshiyuki Takano

Kimihiro Nakamura

Mitsuru Tamai

Teizo Takahama

Tadanori Yuhara

Mikihiko Matsuda

Hironobu Yao

Shinichi Souma

Kazuaki Kitamura

An electrostatic capacity type differential pressure detector wherein capacitances are formed between a diaphragm as a movable electrode which is subjected to displacement depending on a differential pressure and fixed electrodes which are arranged on opposite sides of the diaphragm. Each of the fixed electrodes has a first electrically conductive plate closely adjoining and confronting a surface of a central portion of the diaphragm. An annular support is joined to the surface of a circumferential edge portion of the diaphragm and is spaced from and surrounds the outer circumferential surface of the first electrically conductive plate. A solid insulator completely fills an annular space between the first electrically conductive plate and the annular support and is spaced from the diaphragm. An insulating plate is commonly joined to each surface of the annular support and the first electrically conductive plate on the side of the annular support and conductive plate opposite the diaphragm; and a second electrically conductive plate is joined to the surface of the insulating plate opposite the diaphragm and is electrically connected with the first electrically conductive plate. There is a pressure introducing hole extending through the first and second electrically conductive plates and through the insulating plate. Both the first electrically conductive plate and the annular support are composed of silicon, the insulator being composed of a glass material which has a thermal expansion coefficient substantially that of silicon.

Electrostatic capacity type differential pressure detector

The present invention is directed to a capacitive differential pressure detector comprising a diaphragm disposed between two electrodes. In a first embodiment, each of the electrodes comprises two conductive plates with an insulator disposed therebetween. Step-like portions are formed in the conductive plate nearest the diaphragm. In a second embodiment, the plate nearest the diaphragm is insulative with a conductive film formed thereon. In a third embodiment, at least one groove is formed in the plate nearest the diaphragm. The groove is formed in a surface of the plate which faces the diaphragm. The groove also intersects a pressure guide hole. In a fourth embodiment, a substrate is disposed on a surface of the plate farthest from said diaphragm. In a fifth embodiment, an insulating layer has the same coefficient of thermal expansion as the conductive plates. In a sixth embodiment, the diaphragm is etched in order to form a circular flexible part, a centrally disposed displacing part, and a bonding part.

Capacitive differential pressure detector

A pressure detector for measuring the pressure of a pressurized fluid by means of electrostatic capacitance comprising a diaphragm displaceable in response to the pressure, and a pair of fixed electrodes, one of each of the fixed electrodes being located on each side of the diaphragm and being electrostatically capacitively coupled to the diaphragm, each of the fixed electrodes being shaped to essentially eliminate electrostatic capacitances that are not differentially linear with respect to the pressure.

Electrostatic capacitance type pressure detector

An electrostatic capacitive pressure sensor having two silicon diaphragms electrostatically bonded to opposite faces of an insulating member to form two measuring chambers. A silicon base is coupled to the first diaphragm to form a pressure chamber. The insulating member is provided with a through-hole electrode. The electrode and the two silicon diaphragms are operative to measure pressure in the pressure chamber by measuring changes in capacity in the measuring chambers.

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Kanagawa, Japan

Toshiyuki Takano