Hitachi, Ltd.

Hitachi Automotive Engineering Co., Ltd.

Yukiko Sugisawa

Norio Ichikawa

Masayoshi Suzuki

Takao Sasayama

Junichi Horie

Yuuji Ogasawara

Keizi Hanzawa

Masahiro Matsumoto

Sadayasu Ueno

Masayuki Miki

Seiko Suzuki

Shigeki Tsuchitani

Kanemasa Sato

Tomoyuki Tanaka

Masanori Kubota

Hiromichi Ebine

Yasuhiro Asano

A capacitance acceleration sensor and method of making same are disclosed. A capacitance acceleration sensor includes a movable electrode etched from a silicon plate which is clamped between two solid dielectric plate members of glass, silicon oxides, or oxygen oxides. Static electrodes are secured to surfaces of the dielectric members facing opposite the movable electrode, thereby providing easy manufacturing assessibility for leadout wires from these electrodes. In certain embodiments, the movable electrode is formed integrally with a monocrystalline silicon plate member which also contains an integrated circuit for generating an output acceleration signal in response to movement of the movable electrode when the assembly experiences acceleration forces.

Method of making a capacitance type acceleration sensor

A capacitance acceleration sensor includes a movable electrode etched from a silicon plate which is clamped between two solid dielectric plate members of glass, silicon oxides, or oxygen oxides. Static electrodes are secured to surfaces of the dielectric members facing opposite the movable electrode, thereby providing easy manufacturing assessibility for leadout wires from these electrodes. In certain embodiments, the movable electrode is formed integrally with a monocrystalline silicon plate member which also contains an integrated circuit for generating an output acceleration signal in response to movement of the movable electrode when the assembly experiences acceleration forces.

Capacitance type acceleration sensor

A semiconductor acceleration sensor is formed by a cantilever having a conductive movable electrode of predetermined mass at one end, at least one pair of fixed conductive electrodes which are stationary with respect to the movable electrode located on opposing sides of the movable electrode, and gaps provided between the movable electrode and the fixed electrodes. To prevent the movable electrode becoming fused to the contacted fixed electrode, in a first aspect of this invention, an insulating layer is provided between the movable electrode and fixed electrodes, the layer being either on the movable electrode or on the fixed electrodes and in a second aspect the movable electrode or, preferably, the fixed electrodes, are formed of a high melting point material. In such a second aspect, to improve adhesion between the high melting point material and a substrate to which the fixed electrodes are mounted, a lower melting point material is firstly coated on the substrates. A sensor detector unit processing circuit has the output characteristic of the circuit digitally adjusted by suitable switching of a plurality of resistors, and the sensor chip and the detector unit integrated circuit may be located on a common base and mounted in a hermetically sealed chamber to prevent adverse environmental effects affecting operation of the sensor and detector unit assembly. A gas having a dew point of -40.degree. C. or lower is, advantageously, charged into the hermetically sealed chamber.

Semiconductor acceleration sensor and vehicle control system using the

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Hitachinaka, Japan

Yukiko Sugisawa