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PHYSICAL QUANTITY SENSOR

  • US 20150168437A1
  • Filed: 05/28/2013
  • Published: 06/18/2015
  • Est. Priority Date: 05/29/2012
  • Status: Active Grant
First Claim
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1. A physical quantity sensor comprising:

  • a substrate;

    a drive weight supported by the substrate via a first spring;

    a detection weight supported by the drive weight via a second spring, the detection weight including a detection movable electrode; and

    a detection fixed portion including a detection fixed electrode that is arranged to be opposed to the detection movable electrode,wherein;

    an application of a physical quantity, while the drive weight is driven and vibrated, displaces the detection movable electrode and the detection weightto change an interval between the detection movable electrode and the detection fixed electrode;

    the physical quantity is detected based on the changed interval;

    f1 is defined as a resonance frequency in same-phase mode where the drive weight moves following the application of the physical quantity in a direction identical to a direction in which the detection weight moves;

    f3 is defined as a resonance frequency in same-phase absorptive mode where the drive weight moves following the application of the physical quantity in a direction opposite to a direction in which the detection weight moves;

    n is defined as an integer;

    the resonance frequency f3 in the same-phase absorptive mode is greater than the resonance frequency f1 in the same-phase mode;

    Δ

    f3 is defined as an absolute value that is a difference between the resonance frequency f3 in the same-phase absorptive mode and a value that is the product of the resonance frequency f1 in the same-phase mode multiplied by n;

    D is defined as an avoidance difference that indicates a degree of deviation of the absolute value Δ

    f3 from the resonance frequency f1 in the same-phase mode; and

    a relation where the absolute value Δ

    f3 is greater than a value that is the product of the resonance frequency f1 in the same-phase mode multiplied by the avoidance difference D is satisfied and, simultaneously, the avoidance difference D is provided to be greater than 0%.

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