Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Yoshihiro Yokota

Seiko Suzuki

Shigeki Tsuchitani

Satoshi Shimada

Masahiro Matsumoto

Hiroshi Kuroiwa

Masayoshi Kaneyasu

Seiichi Ugai

Akira Koide

Masahide Hayashi

Masayuki Miki

Shotaro Naito

Kazuo Kato

Toshihiko Suzuki

A three-dimensional acceleration sensor capable of detecting a small acceleration value and even an acceleration value amounting up to 100 G occurring in the event of a collision has a diaphragm for linking a frame and a massive part, and diaphragms and beams for linking the massive part and a central part. These elements are formed by working a single crystalline silicon plate. Gaps between the massive part and opposing electrodes are changed by acceleration applied to the massive part. A circuit connected to terminals detects the changes in gaps as changes in capacitances and determines direction and level of the applied acceleration.

Airbag system using three-dimensional acceleration sensor

A detector for detecting a physical quantity as a quantity of electricity has a detection portion, a portion for stimulating the detection portion and a signal processing portion, wherein a calibration signal is supplied from the signal processing portion to the detection portion via the stimulating portion so as to measure a specific response of the detection portion, whereby self-calibration and correction of the characteristic of the detector are performed in accordance with an amount of a change in the response.

Detector having self-calibration function

A semiconductor accelerometer includes a mass portion formed at a center of a silicon plate, a frame portion formed around the circumference of the silicon plate so as to surround the mass portion and a diaphragm portion formed in the silicon plate between the mass portion and the frame portion so as to bridge the mass portion with the frame portion, one of major surfaces of the silicon plate serving as a common continuous major surface for the mass portion, frame portion and diaphragm portion. Piezoresistance elements are formed on the common continuous major surface at the diaphraqm portion and an additional Au film is formed on the common continuous major surface at the mass portion. The additional Au film constitutes in combination with the mass portion a weight which responds to an acceleration acting thereon. The mass of the additional Au film is selected in such a manner that the center of gravity of the weight is located within an area in the mass portion having a depth corresponding to the thickness of the diaphragm portion.

Semiconductor accelerometer

A three-dimensional acceleration sensor capable of detecting a small acceleration value and even an acceleration value amounting up to 100G occurring in the event of a collision comprises a diaphragm for linking a frame and a massive part and diaphragms and beams for linking the massive part and a central part. These elements are formed by working a single crystalline silicon plate. Gaps between the massive part and opposing electrodes are changed by acceleration applied to the massive part. A circuit connected to terminals detects the changes in gaps as changes in capacitances and determines direction and level of the applied acceleration.

Three-dimensional acceleration sensor and airbag using the same

A signal processor (5) is coupled to a detector (6) for detecting a physical quantity. The signal processor has a zero adjustment memory (14) and a sensitivity adjustment memory (16). The zero adjustment memory and the sensitivity adjustment memory have a number of switches (20, 20A, 20', 20'), respectively. These switches are changed over digitally using a zener zapping method or a polysilicon fuse method at each switch to adjust the characteristics of the detector.

Sensor

Disclosed is an acceleration detector which has an electrically conductive mass portion formed at a free end of a cantilever, and fixed electrodes arranged opposite to the mass portion through a gap so that the value of acceleration is detected on the basis of the change of capacitance between the mass portion and the fixed electrodes, and in which at least one space is formed in the inside of the mass portion to lighten the weight of the mass portion to thereby widen the range of measurement.

Capacitive acceleration detector having reduced mass portion

A detector for detecting a physical quantity as a quantity of electricity has a detection portion, a portion for stimulating the detection portion and a signal processing portion, wherein a calibrating signal is supplied from the signal processing portion to the detection portion via the stimulating portion so as to measure a specific response of the detection portion whereby a self-calibration and a correction of the characteristics are performed in accordance with the amount of the change in the response.

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Katsuta, Japan

Yoshihiro Yokota