Browse Prior Art Database

PVDF Based Acoustic Intensity Transducer

IP.com Disclosure Number: IPCOM000104587D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 86K

Publishing Venue

IBM

Related People

Crawforth, L: AUTHOR [+2]

Abstract

Disclosed is a transducer incorporation poly-vinylidene di-fluoride (PVDF), a piezo-electric material, for the purpose of extending the frequency range of acoustic intensity measurements.

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PVDF Based Acoustic Intensity Transducer

      Disclosed is a transducer incorporation poly-vinylidene
di-fluoride (PVDF), a piezo-electric material, for the purpose of
extending the frequency range of acoustic intensity measurements.

      Fig. 1 illustrates the basic components of the transducer.  It
consists of two separate sound pressure sensing elements utilizing
PVDF film.  The appropriate electrode and shielding layers are shown
which serve to eliminate the pyro-electric effect as well as decouple
the two pressure measurements.  Acoustic intensity is obtained by
measuring both the sound pressure and sound pressure gradient across
the device.  The sound pressure gradient is approximated by the
difference of the two individual pressure measurements P sub a and P
sub b, divided by the element spacing, &Delta.R [1].  The separation,
&Delta.R, can be made small by using the PVDF film, and has the
effect of extending the frequency range of the intensity measurement
to over 100kHz as compared with the 10 kHz range of devices using
conventional microphone technologies [2].  PVDF can be deposited in
very thin layers and patterned using silk screening techniques in a
number of configurations.

      Fig. 2 illustrates an array application in which several
transducer elements could be manufactured in the form of a tape.  By
positioning the transducer array around some form of machinery, sound
power measurements could be performed outside of an anechoic chamb...