Mitsubishi Petrochemical Company Limited

Fumio Ohta

Nobuo Tanaka

Akira Gohkura

Yoshinao Mukasa

Masahiro Sasaki

Tomonobu Tomita

Kazuo Yorihiro

This invention relates to an acceleration sensor device suitable for self-checking while a vehicle is being driven and a self-checking circuit therefor. An acceleration sensor device for self-checking while driving is comprised of a planar vibrator having a piezoelectric area and a non-piezoelectric area and a plurality of first electrodes provided on an upper face of the piezoelectric area of the planar vibrator. At least one second electrode is provided on an upper face of the non-piezoelectric area of the planar vibrator, and a third electrode is provided on the lower face of the planar vibrator. Inputs to the self-checking circuits provide an output that represents the operating state of the acceleration sensor.

Acceleration sensor suitable for self-checking and a self-checking

This invention relates to an acceleration sensor system having a self-checking operation of an air bag safety system while a vehicle is being driven. An acceleration sensor element suitable for self-checking while a vehicle is driven is obtained by a planar piezoelectric element supported so that it can vibrate, a detecting electrode provided on an upper face of the planar piezoelectric element, and an actuator to add vibrations at a predetermined frequency to the planar piezoelectric element. A sensitivity checking circuit generates a sensitivity checking signal representing sensitivity of an acceleration sensed from a detected signal. A signal processing circuit generates an acceleration signal representing the applied acceleration to the acceleration sensor from the detected signal. An operation checking circuit generates a self-checking signal representing the operational state of the acceleration sensor system by checking the operation of the signal processing circuit and the acceleration sensor from the acceleration signal and the sensitivity checking signal.

Acceleration sensor unit having self-checking function

This invention relates to an acceleration sensor having less output drift due to temperature change and noise due to external induction which includes a piezoelectric device formed of a piezoelectric member having one or more electrodes provided on each of sides thereof and a lining member of low linear expansion coefficient adhered to one side thereof. A low linear expansion coefficient circuit substrate is provided having the piezoelectric device adhered to one side thereof and having a signal processing electronic circuit formed on the other side thereof. A cabinet having three layers, including an internal conductive resin layer, an adiabatic resin layer, and an external conductive metal layer, completely enclose the piezoelectric device and the circuit substrate.

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Yokkaichi, Japan

Fumio Ohta