Kabushiki Kaisha Toyota Chuo Kenkyusho

Toyoda Koki Kabushiki Kaisha

Osamu Tabata

Susumu Sugiyama

Keiichi Shimaoka

Hazime Inagaki

Shiro Kuwahara

Tomoyuki Kitano

Shizuki Sakurai

Tomio Nagata

A digital capacitive sensing device comprises: a reference capacitor having a reference capacitance unaffected by a force to be measured; a reference pulse signal generating circuit which generates a reference pulse signal of a frequency corresponding to the reference capacitance; a sensing capacitor having capacitance variable according to the magnitude of the force; a measuring pulse signal generating circuit having a construction similar to that of the reference pulse signal generating circuit and capable of generating a measuring pulse signal of a frequency corresponding to the capacitance of the sensing capacitor; and a differential arithmetic circuit which adds the number of pulses of the reference pulse signal in a predetermined time interval to a set value and subtracts the number of pulses of the measuring pulse signal in a predetermined time interval from the set value. The reference pulse signal generating circuit is capable of compensating a zero point temperature characteristic of a detection value, and the measuring pulse signal generating circuit is capable of compensating a detection sensitivity temperature characteristic.

Capacitive sensing device

A semiconductor pressure sensor having a diaphragm formed over the surface of a semiconductor substrate by thin film forming technique is provided. The sensor comprises: a sacrificial film including a vanishable portion covering a pressure receiving region on the major surface of the semiconductor substrate and a diaphragm support portion covering the periphery of the pressure receiving region, the vanishable portion having an isotropic etching property along the pressure receiving region and the diaphragm support portion having an etching-resistant property; an insulation diaphragm film having an etching-resistant property formed on the major surface of the semiconductor substrate over the sacrificial film; at least one etching solution inlet port formed through the insulation diaphragm film to reach the vanishable portion of the sacrificial film; a reference pressure chamber formed by etching and removing at least the vanishable portion of the sacrificial film with an etching solution poured through the inlet port; and at least one strain gauge formed on the insulation diaphragm film in place at the pressure receiving region. The peripheral region of the movable diaphragm can be formed into a flat configuration without any stepped structure. Thus, the semiconductor pressure snesor has an improved characteristics.

Semiconductor pressure sensor

A semiconductor flow velocity sensor having a semiconductor substrate and an electrical heating unit arranged on the substrate. The sensor located in the fluid flow to be measured can electrically detect the radiation from the heating unit which varies depending on the velocity of fluid flow. Thermal insulator is provided between the semiconductor (silicon) substrate and the heating unit so as to thermally shield the substrate from the heating unit. On the thermally isolated area of the substrate is provided an external sensor circuit so as to enable to increase the integration of the sensor.

Semiconductor flow velocity sensor

Growing community of inventors

Aichi, Japan

Osamu Tabata