Matsushita Electric Works, Ltd.

Sumio Akai

Hitoshi Yoshida

Hisakazu Miyajima

Kazushi Kataoka

Daisuke Wakabayashi

Koji Goto

Makoto Morii

A semiconductor acceleration sensor comprises: a frame having an opening inside thereof; flexible beams extending from the frame to the inside of the opening of the frame; a weight suspended from and supported by the beams so that the weight can freely move; piezoresistors to be mounted on the beams and to vary the resistance values in response to accelerations which work on the piezoresistors. The frame comprises damper plate portions, each of which covers a part of the opening spanning from a corner portion of two neighboring sides of the frame on the side of the opening to the inside of the opening, and each of which serves serve as a stopper to limit movement of the weight. The weight has corner portions which face the corner portions, respectively, and each of which is chamfered to have a shape of arc or a polygonal line consisting of at least three sides as seen in plan view. Thereby, the breaking strength of each stopper is increased, and hence a semiconductor acceleration sensor having superior shock resistance can be obtained.

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Otsu, Japan

Sumio Akai