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Ultrasonic transducer lab
1/22/13 1
Work package 4 (WP4) on project: Subsea sensors for oil &
gas
- Frank Melands - Svein Jacobsen - Adit Decharat (PhD) - Sanat
Wagle (post. Doc.)
External partner: Fraunhofer IAP, Berlin, Germany
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Subsea sensors for oil and gas
l Supported by NFR for 5 years (33 mil) l Can apply for
additional 3 years l Includes 5 work pagages
WP1: Electromagnetic methods for oil and gas exploration WP2:
Ultrasound Gas Leak Detection WP3: Raman-spectroscopy for subsea
detection of methane WP4: Process Research and Development of New
Ultrasonic
Transducers WP5: Technology entrepreneurship and
university-industry
technology transfer in geographically dispersed regions
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Outline
What is an ultrasonic transducer?
How can we make them?
Experimental characterization
Numerical modeling
Applications of ultrasonic transducers & sensors
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Functional polymers (Polymers with advanced optic and/or
electronic properties: Wikipedia)
OLED (organic LED) Organic (polymer) solar cells Conducting
polymers Organic transistors Flexible displays (Electronic paper)
Identification cards (RFID) Piezoelectrical polymers
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Printed electronics: Roll to roll (R2R)
1/22/13 5
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Ultrasonic transducers
Piezoelectric effect Inverse piezoelectric effect
Side view - transducer
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Polymer (PVDF & PVDF copolymers)
monomer (basic molecule)
polymer (different phases)
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How do we make a piezoelectric polymer transducer? (typical
solvent based polymer processing)
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Solid material Fluid (ink, paint) Solid film (after heating)
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Piezoelectric polymers PVDF and its copolymers
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PVDF film sensors (MSI)
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Main activities on WP4
First transducers delivered by project partner (Fraunhofer IAP,
Germany)
Screen printed transducers (Acreo AB)
Prototyping lab at UiT for polymer sensors
Characterization & signal processing lab at UiT for
ultrasonic sensors
1/22/13 10
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First transducer delivery from Fraunhofer IAP (ink-jet printed
or sputtered electrodes)
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Screen printed transducers
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Screen printer
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Screen printing by Acreo AB
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+ (a) PEDOT : PSS ink
(Bottom electrode) (C) PEDOT : PSS ink
(Top electrode) (b) P(VDF-TrFE) fluid
(d) Carbon ink on the arm of top electrode
(e) silver ink on the top for ground and better connectivity
+
Screen printed transducers on A4 sheet of PEI
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Surface roughness measurements and 3-D image
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KLA/Tencor P6 Surface profiler
Thickness of PVDF : 6.5 m Thickness of PEDOT:PSS : 1.0 m
Roughness above active area Ra : 0.3 to 0.5 m
Stylus force: 2 mg
(a) 1 mm x 1 mm square (b) 1.5 mm dia. circular
(c) 2.0 mm dia. circular (d) 2.5 mm dia. circular
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Polarization of ultrasonic transducer
Transducer : Cured at 130C for 40 min Voltage : 100 MV/m and
different Type : sinusoidal pulse (10 cycles) Frequency : 0.250 Hz
Temperature : Room temperature
-100 0 100-0.1
0
0.1 16 MV/m 32 MV/m 56 MV/m 71 MV/m 103 MV/m
Dis
plac
emen
t (C
/m2 )
Electric Field (MV/m)
-100 0 100-0.1
0
0.1
Dis
palc
emen
t (C
/m2 )
Electric Field (MV/m)
2.5 mm dia 2.0 mm dia 1.5 mm dia 1.0 mm Sq.
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Ultrasonic measurement Arbitrary wave generator
Digital storage Amplifier
PVDF Electrodes
PEI Substrate
Acoustic signal (Rx)
Ultrasonic testing (input pulse) Type : Gaussain (2nd
derivative) PRF : 250 KHz Voltage : 10 Vpp PEI thickness : 0.85
mm
Acoustic wave
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Ultrasonic measurement
Acoustic reflection from back side of PEI
1.0 mm 1.5 mm
2.5 mm
2.4 2.5 2.6 2.7-0.2
-0.1
0
0.1
0.2
Time, t (s)
Inte
nsity
, I (
V) 2.0 mm
Corresponding FFT
PVDF Electrodes
PEI Substrate Acoustic wave
1.0 mm 1.5 mm
2.5 mm
20 40 60 80 100
0.005
0.01
0.015
0
2.0 mm
Inte
nsity
, I (
V)
Frequency, F (MHz)
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Local lab at UiT for polymer sensors
Polymer (PVDF copolymer) deposition Curing and deposition of
conductive inks (based
on Ag nanoparticle) Substrate treatment for adhesive enhancement
Solvents useful for multiple PVDF layers
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First one layer transducer produced Dec. 2011
Two layer transducer produced Oct. 2012
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Printed multilayer transducers
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Dimatix ink-jet printer (at Fraunhofer)
GIX Microplotter II (at UiT)
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Plasma instruments
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sputter coater (Cressingon 208HR) surface treatment/cleaning
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Objective To develop fabrication process of ultrasonic polymer
transducer
in order to implement an array transducer of multiple layers for
high sensitivity and steerable beam transducer on flexible
substrate.
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G1
G2
S1
G5
G4
G3
S5S4S3S2
Array pixlesS
ubst
rate
(2-3 mm)
Piezoelectric filmPiezoelectric film (L 1 )
Backing SubstrateBacking Substrate
Upper e l ec t r odeE l ec t r ode 2
L ower el ec t r odeE l ec t r ode 1
Piezoelectric film
Piezoelectric film
L 2
L n
E l ec t r ode 3
E l ec t r ode n
~10-20 m
~0.1-2 m
+
-
-
2n
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Transducer implementation 2 PVDF layers
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Spin coat processes
Transducer array
Ag ink Etching
Resist removal
Patterned etching resist
Ag ink electrode
Etchant solution
Piezoelectric filmPVDF L 1
Backing SubstrateBacking Substrate
L ower el ec t r odeE l ec t r ode 1
Upper e l ec t r odeE l ec t r ode 2PVDF solution (L 2)
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Applications of multilayer PVDF transducers/sensors
Ultrasonic imaging in NDT and medicine
Continuous wave (CW) transducers
Gas detection (in cooperation with WP2)
Energy harvesting
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Characterization & signal processing lab at UiT for
ultrasonic sensors
1/22/13 24
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Improved SNR from coded ultrasonic sequences
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0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50.1
0
0.1
Pote
ntial
(V)
(a) measured potential on PVDF electrode
Golay seq. 1Golay seq. 2
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 50.02
0
0.02
Curre
nt (m
A) (b) measured current (coded seq.)
0 0.5 1 1.5 2 2.5
101
Corr.
value
(arb
)
(c) correlated seq. 1 and 2
0 0.5 1 1.5 2 2.5
202
Corr.
value
(arb
)
(d) sum correlated seq.
0 0.5 1 1.5 2 2.50.02
0
0.02
Time (s)
Pote
ntial
(V) (e) measured current (single pulse)
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Applications: Energy harvesting
1/22/13 26
Backpack (piezo straps) Michigan Technological University,
Arizona State University
Shoes Louisiana Tech University
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Energy harvesting
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Piezo tree (PVDF leaves) Cornell University
