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Capacitive pressure sensor

  • US 4,864,463 A
  • Filed: 04/19/1988
  • Issued: 09/05/1989
  • Est. Priority Date: 04/19/1988
  • Status: Expired due to Term
First Claim
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1. A capacitive pressure sensor comprising:

  • a housing including a pair of spaced apart diaphragms matched in compliance to vibrate and deflect in substantial unison in response to vibratory and acceleration forces, respectively;

    an outer pressure responsive one of said pair of diaphragms movably cooperating with said housing to bound a reference-pressure chamber within which is movably disposed the other of said pair of diaphragms;

    said other diaphragm carrying a first pair of spaced apart planar electrodes confronting said one diaphragm and each of a certain geometric shape, and a first planar shield electrode having a portion circumscribing said first pair of electrodes and a cross bar portion interposing between said first pair of electrodes;

    said one diaphragm carrying a second pair of spaced apart planar electrodes confronting said other diaphragm and said first pair of electrodes thereon and each of said certain geometric shape;

    said first pair of electrodes and said second pair of electrodes being congruent to define a respective pair of variable capacitors each of substantially identical value and varying in capacitance value simultaneously in union as said one diaphragm moves in response to external fluid pressure, whereby said variable capacitors remain of substantially identical value in response to external fluid pressure acting on said sensor, and said capacitance values being substantially immune from said vibration and acceleration forces.

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