Capacitative pressure sensor

  • US 7,121,145 B2
  • Filed: 10/18/2004
  • Issued: 10/17/2006
  • Est. Priority Date: 10/18/2004
  • Status: Expired due to Fees
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First Claim
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1. A pressure sensor for sensing a fluid pressure, the pressure sensor comprising:

  • a chamber partially defined by a flexible membrane, the flexible membrane at least partially formed from conductive material, and the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and a fluid pressure;

    a conductive layer within the chamber spaced from the flexible membrane; and

    , associated circuitry incorporating the flexible membrane and the conductive layer;

    such that,the conductive layer and the flexible membrane form capacitor electrodes and the deflection of the flexible membrane changes the capacitance which the associated circuitry converts into an output signal indicative of the fluid pressure;

    wherein, the conductive layer is arranged such that deflection of the membrane towards the conductive layer can displace the fluid from between the membrane and the conductive layer; and

    a second chamber with a second membrane, the second chamber being sealed from the fluid pressure and the second membrane deflecting from a predetermined pressure difference in the second chamber;

    wherein,the associated circuitry converts the deflection of the second membrane into an adjustment of the output signal to compensate for the temperature of the sensor.

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