Linear capacitive pressure sensor

A pressure sensing device, comprising:

• a substrate having first and second cavities defined therein;
• a passage connecting the first and second cavities to external air pressure;
• a first pressure sensor comprising:
• a first membrane suspended over the first cavity, wherein a change in external air pressure causes out-of-plane movement of the first membrane;
• a first frame slidably suspended over the first membrane;
• wherein the first frame includes:
• a segment mechanically connected to the first membrane and directly mechanically disconnected from other portions of the first frame, and at least one projection extending from the first frame;
• and
• at least one first spring structure mechanically connected to the at least one projection and the segment, wherein out-of-plane movement of the first membrane applies an out-of-plane force to the at least one first spring structure which in turns translates the out-of-plane force to an in-plane force applied to the first frame in a first direction to thereby cause lateral sliding movement of the first frame in the first direction with respect to the substrate;
• and
• at least one first anchored spring anchored to the substrate and extending over the first membrane in a spaced apart fashion thereto to be mechanically connected to the at least one projection, the at least one first anchored spring serving to constrain the first frame from out-of-plane movement;
• and
• a second pressure sensor comprising:
• a second membrane suspended over the second cavity, wherein a change in external air pressure causes out-of-plane movement of the second membrane;
• a second frame slidably suspended over the second membrane;
• wherein the second frame includes:
• a segment mechanically connected to the second membrane and directly mechanically disconnected from other portions of the second frame, and at least one projection extending from the second frame;
• and
• at least one second spring structure mechanically connected to the at least one projection of the second frame and the segment of the second frame, wherein out-of-plane movement of the second membrane applies an out-of-plane force to the at least one spring structure which in turns translates the out-of-plane force to an in-plane force applied to the second frame in a second direction opposite to the first direction to thereby cause lateral sliding movement of the second frame in the second direction with respect to the substrate;
• and
• at least one second anchored spring anchored to the substrate and extending over the second membrane in a spaced apart fashion thereto to be mechanically connected to the at least one projection, the at least one second anchored spring serving to constrain the second frame from out-of-plane movement;
• and
• a first capacitive sensor associated with the first frame for detecting sliding in-plane movement of the first frame with respect to the substrate;
• and
• a second capacitive sensor associated with the second frame for detecting sliding in-plane movement of the second frame with respect to the substrate.