Omni-directional ultrasonic transducer apparatus having controlled frequency response

  • US 6,239,535 B1
  • Filed: 03/30/1999
  • Issued: 05/29/2001
  • Est. Priority Date: 03/31/1998
  • Status: Expired due to Term
First Claim
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1. A transducer apparatus comprising:

  • a spool member having a body portion and first and second elevated regions formed on the body portion;

    a piezoelectric film surrounding said spool member and unsecured thereto, said piezoelectric film spaced apart from the body portion of said spool member by an elevation of the elevated regions, thereby forming a predetermined gap between said piezoelectric film and the body portion of said spool member, wherein the predetermined gap is sufficiently sized for enabling a predetermined resonance frequency in said piezoelectric film to control the resonance frequency of the transducer.

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