Internally shock caged serpentine flexure for micro-machined accelerometer

A micro-machined electromechanical sensor (MEMS) device, comprising:

• a substantially planar proof mass suspended for in-plane motion from a relatively stationary frame by pluralities of first and second pairs of spaced-apart resiliently flexible elongated flexure members, wherein:
• each of the first pairs of elongated flexure members are interconnected at respective first ends, and adjacent pairs of the elongated flexure members are interconnected at respective second ends of adjacent elongated flexure members with respective second ends of first and last flexure members being interconnected between a first end of the proof mass and the frame,
• each of the second pairs of elongated flexure members are interconnected at respective first ends, and adjacent pairs of the elongated flexure members are interconnected at respective second ends of adjacent elongated flexure members with respective second ends of first and last flexure members being interconnected between a second end of the proof mass and the frame, and
• a spring rate associated with one of the elongated flexure members is different from a spring rate associated with a different one of the elongated flexure members;
• a promontory mass formed between adjacent second pairs of the elongated flexure members on one end of a relatively short crosswise member interconnecting the respective first ends of a pair one of the first pairs of the elongated flexure members;
• and
• one or more comb-type capacitive pickoff sensors formed between the proof mass and the frame and structured for changing capacitance as a function of a movement of the proof mass relative to the frame.

A micro-machined electromechanical sensor (MEMS) device, comprising:

• a silicon substrate having substantially parallel and planar spaced-apart surfaces;
• a proof mass formed in the substrate;
• a frame formed in the substrate surrounding the proof mass;
• a plurality of capacitive pickoff sensors formed between the proof mass and the frame and structured for changing capacitance as a function of an in-plane movement of the proof mass relative to the frame;
• a plurality of serpentine flexures formed in balanced configuration between the proof mass and the frame and structured for enabling the in-plane movement of the proof mass relative to the frame, one or more of the serpentine flexures comprising a plurality of substantially parallel and spaced-apart resiliently flexible elongated flexure members that are arranged substantially crosswise to a direction of the in-plane movement of the proof mass relative to the frame and are interconnected at opposite ends of alternate pairs of the elongated flexure members;
• a plurality of relatively short interconnecting members arranged crosswise to the longitudinal axes of the elongated flexure members and interconnecting opposite ends of alternate pairs of the elongated flexure members in a serpentine configuration;
• and
• a promontory mass formed between the serpentine flexures, the promontory mass being positioned at one end of one or more of the relatively short interconnecting members and being sized to span a part of the distance between adjacent elongated flexure members.

A micro-machined electromechanical sensor (MEMS) device having a serpentine flexure, the device comprising:

• a relatively stationary frame formed in a substrate having substantially parallel and planar spaced-apart surfaces;
• a moveable proof mass that is formed in the substrate;
• and
• a plurality of serpentine flexures suspending the proof mass from the frame, one or more of the serpentine flexures comprising:
• a plurality of elongated flexure members each formed in the substrate between the spaced-apart surfaces thereof,
• a relatively short interconnecting member arranged crosswise to the longitudinal axes of the elongated flexure members and interconnecting opposite ends of alternate pairs of the elongated flexure members in a serpentine configuration, and
• a small mass formed as an extension formed on one end of one or more of the interconnecting members and extending a part of a distance between adjacent elongated flexure members.

A micro-machined electromechanical sensor (MEMS) device having a serpentine flexure, the device comprising:

• a relatively stationary frame formed in a substrate having substantially parallel and planar spaced-apart surfaces;
• a moveable proof mass that is formed in the substrate;
• and
• a plurality of serpentine flexures suspending the proof mass from the frame, one or more of the serpentine flexures comprising:
• a plurality of elongated flexure members each formed in the substrate between the spaced-apart surfaces thereof,
• a relatively short interconnecting member arranged crosswise to the longitudinal axes of the elongated flexure members and interconnecting opposite ends of alternate pairs of the elongated flexure members in a serpentine configuration, and
• a small mass formed as an extension formed on each of two opposite ends of one or more of the interconnecting members and extending a part of a distance between adjacent elongated flexure members.

A micro-machined electromechanical sensor (MEMS) device having a serpentine flexure, the device comprising:

• a relatively stationary frame formed in a substrate having substantially parallel and planar spaced-apart surfaces;
• a moveable proof mass that is formed in the substrate;
• and
• a plurality of serpentine flexures suspending the proof mass from the frame, one or more of the serpentine flexures comprising:
• a plurality of elongated flexure members each formed in the substrate between the spaced-apart surfaces thereof wherein a spring rate of one or more of the serpentine flexures progressively changes between the proof mass and the frame, and
• a small mass extending a part of a distance between adjacent elongated flexure members.