Fuji Electric Co., Ltd.

Kimihiro Nakamura

Toshiyuki Takano

Mitsuru Tamai

Teizo Takahama

Tadanori Yuhara

Mikihiko Matsuda

Masato Takahashi

Takahiro Kudo

Nobuhisa Kato

Michihiko Tsuruoka

Hironobu Yao

Shuji Tsukamoto

Kazuaki Kitamura

Shinichi Souma

Shinichi Soma

A capacitance-based pressure detecting apparatus detects a pressure applied to a diaphragm based on a capacitance which varies depending on the change in portion of the diaphragm. The pressure detecting apparatus comprises a diaphragm which changes position depending on a differential pressure between a first pressure and a second pressure, a first electrode which is provided opposite a first plane of the diaphragm and forms, together with the diaphragm, a first capacitor, a second electrode which is provided opposite a second plane of the diaphragm and forms, together with the diaphragm, a second capacitor, a third capacitor altering a capacitance according to the first pressure, a detecting unit for detecting the capacitance of the first through third capacitors, and an operation unit for obtaining a pressure applied to the diaphragm based on the capacitance of the first and second capacitors, and amending the obtained pressure based on the capacitance of the third capacitor.

Pressure detecting apparatus for measuring pressure based on detected

A time measurement device for measuring a duration of an input signal based on a clock signal comprises a first gate for outputting a gate signal based on an input signal; a first holding circuit for holding the gate signal at the time of falling of the clock signal; a second holding circuit for holding the gate signal at the time of rising of the clock signal; a second gate for passing the clock signal according to either of the widths of output signals of the first and second holding circuits; a third holding circuit for holding an output state of the second holding circuit at the timing of a leading edge of an output of the first holding circuit; a fourth holding circuit for holding an output state of the second holding circuit at the timing of a trailing edge of an output of the first holding circuit; and a counter for counting the clock signal output from the second gate. The count value is corrected based on the outputs of the third and fourth holding circuits.

Time measurement device

In a capacitive differential pressure detector, an insulating plate (1) of a fixed electrode is covered with a gold conductive film. A conductive film (2) integrally includes an entire inner area (2a) of a center hole (1a), a square ring-shaped area (2b) surrounding the center hole (1a) on the side opposite to the conductive plate (12) and a band-shaped area (2c) extending therefrom in a centrifugal direction to reach the outer periphery. The conductive film (2) is electrically communicated with the conductive plate at the terminating position of the entire inner area (2a) and also with aluminum films at the terminating position of the band-shaped area (2c). Therefore, the total area of the ring-shaped area (2b) and the band-shaped area (2c) can be decreased so that Cs1+Cs2 is decreased to improve the static pressure span characteristic.

Capacitive differential pressure detector

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.

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 capacity type pressure detector having a central diaphragm, which is deformed by pressure, and a fixed electrode on each side of the diaphragm. Each of the fixed electrodes includes a first electrically conductive plate confronting the diaphragm, an insulating plate joined to the first conductive plate, and a second electrically conductive plate joined to the first plate. An annular support joined to the diaphragm and to the insulating plate surrounds but is insulated from the first electrically conductive plate. A hole in the electrode introdues pressure into a space defined by the electrode and the diaphragm.

Electrostatic capacity 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.

Growing community of inventors

Kanagawa, Japan

Kimihiro Nakamura