Importance

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Abstract

A highly sensitive silicon micro-machined sensor package is provided for use in a micro-g environment that can also resist high shock in excess of 5000 g. The sensor is provided to measure acceleration in cooperation with associated electronics which are required to have electrical contact with sensor elements. The sensor is sealed in a high vacuum environment, and is arranged and designed to be free of temperature induced stress to the sensor. The sensor die package assembly comprises a silicon micro-machined sensor die, a ceramic package, two contact springs, a shorting clip, solder preform, a metal lid and a getter foil for ensuring a good vacuum for an extended period. The sensor die comprises a moving mass with eight supporting flexures on both sides of the proof mass. The proof mass's movement is protected on both sides by a top and a bottom cap. Acceleration applied to the package and the die causes the proof mass to move vertically in relation with the adjacent caps. The changes in distance between the proof mass and the caps in turn generate a change in an electrical signal which corresponds to the capacitance changes between the gaps. The sensor die package arrangement provides that the sensor die be secured within an evacuated ceramic case. Electrical connections made between external contacts of the case and contacts of the sensor die within the case are made through conductive springs, thereby minimizing materials in the interior of the case which would outgass in the vacuum environment.

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First Claim