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Angular velocity sensor and process for manufacturing the same

  • US 6,532,817 B1
  • Filed: 04/27/1999
  • Issued: 03/18/2003
  • Est. Priority Date: 05/06/1998
  • Status: Expired due to Fees
First Claim
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1. An angular velocity sensor comprising:

  • a tuning fork having;

    (a) a first tuning fork member having at least two arms made of single crystalline piezoelectric material and at least one root member joining said arms; and

    a second tuning fork member having a shape generally similar to that of the first tuning fork member, the second fork member made of single crystalline piezoelectric material, said first tuning fork member and second tuning fork member being directly bonded to each other in the thickness direction of the first tuning fork member and second tuning fork member, said bond forming an interface therebetween extending in the width direction thereof without a central electrode and without adhesive disposed between said first and second tuning fork members, such that the polarity of the electric axis of the piezoelectric material for each of the first and second tuning fork members is inverted from each other in the width direction thereof, said tuning fork thereby comprising at least a first tuning fork arm and a second tuning fork arm, each of said first and second tuning fork arms having two opposed side surfaces extending across said interface and two opposed main surfaces orthogonal to said side surfaces, and a tuning fork root between said tuning fork arms;

    (b) sense electrodes disposed across said interface on the two opposed side surfaces of each of said first and second tuning fork arms for detecting the electric charges generated as a result of the angular rotation of said sensor; and

    (c) drive electrodes disposed on two opposed main surfaces of said first tuning fork arm for causing the tuning fork to vibrate in the width direction thereof.

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