Fabrication of curved ceramic/polymer composite transducer for ultrasonic imaging applications by fused deposition of ceramics

Lous, G.; Cornejo, Iván; McNulty, Thomas F.; Safari, A.; Danforth, S.C.

doi:10.1109/isaf.1998.786678

Cited by 8 publications

(8 citation statements)

References 8 publications

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“…The need for an acoustic lens can be avoided, however, by geometrically curving the piezoelectric substrate to create a passive focus. although piezoelectric materials are typically not flexible, piezo-composites, which consist of a matrix of piezoelectric elements embedded into a relatively soft epoxy, typically are flexible and can be geometrically shaped [4], [5]. Using a piezo-composite material as the transducer substrate can be particularly advantageous when generating the elevation focusing in linear-array transducers [6].…”

Section: Introductionmentioning

confidence: 99%

Fabrication and performance of high-frequency composite transducers with triangular-pillar geometry

Brown

Chérin

Yin

et al. 2009

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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A single-element, 40-MHz, 3-mm diameter transducer was fabricated with a geometric focus at 9 mm. The transducer was based on a piezo-composite substrate with triangular-shaped composite pillars. The 2-way bandwidth of 50% and impedance magnitude were in agreement with that predicted using finite-element modeling. A one-way radiation pattern was collected using a needle hydrophone. The one-way -3 dB beamwidth at the geometric focus was measured to be 120 microm and the -3 dB depth of field was 2.5 mm. This is in good agreement with the theoretical predictions of 112.5 microm and 2.4 mm. The triangular-pillar composite transducer was then compared with a transducer with square composite pillars with similar volume fraction of active ceramic. A 9.5 dB reduction in the amplitude of the secondary resonance was found for the triangular-pillar composite as well as a 30% gain in the 2-way pulse bandwidth. A 256-element 30-MHz linear array was fabricated as a preliminary investigation into the use of the triangular pillar as the substrate in a high-frequency linear array transducer. In vivo images were generated with both the single-element and linear-array transducers.

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Section: Introductionmentioning

confidence: 99%

Fabrication and performance of high-frequency composite transducers with triangular-pillar geometry

Brown

Chérin

Yin

et al. 2009

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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“…Because standard array production techniques faces difficulties scaling to higher frequencies [ 59 ], high-frequency transducers can utilize mechanical steering of a single focused element in lieu of an array. Many of these focused single-element transducers have been possible due to the use of flexible piezoelectric composites rather than inflexible piezoelectric ceramics [ 60 , 61 ]. An important advancement for high-frequency arrays has been the development of composites with large triangular pillars to suppress lateral modes while maintaining high sensitivity [ 62 , 63 ].…”

Section: Dual-frequency Transducersmentioning

confidence: 99%

Dual-Frequency Piezoelectric Transducers for Contrast Enhanced Ultrasound Imaging

Martin

Lindsey

et al. 2014

Sensors

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For many years, ultrasound has provided clinicians with an affordable and effective imaging tool for applications ranging from cardiology to obstetrics. Development of microbubble contrast agents over the past several decades has enabled ultrasound to distinguish between blood flow and surrounding tissue. Current clinical practices using microbubble contrast agents rely heavily on user training to evaluate degree of localized perfusion. Advances in separating the signals produced from contrast agents versus surrounding tissue backscatter provide unique opportunities for specialized sensors designed to image microbubbles with higher signal to noise and resolution than previously possible. In this review article, we describe the background principles and recent developments of ultrasound transducer technology for receiving signals produced by contrast agents while rejecting signals arising from soft tissue. This approach relies on transmitting at a low-frequency and receiving microbubble harmonic signals at frequencies many times higher than the transmitted frequency. Design and fabrication of dual-frequency transducers and the extension of recent developments in transducer technology for dual-frequency harmonic imaging are discussed.

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“…an additional advantage of the 1-3 piezocomposite is that it can be geometrically focused to avoid using a lens, because it is more flexible than piezoceramic as a result of the epoxy phase, thereby facilitating mechanical shaping [6], [7]. The absence of a lens in high-frequency ultrasound transducers is preferred, because lenses introduce acoustic attenuation (lens materials commonly used for conventional frequency arrays are highly attenuating) and also degradation of the beamforming caused by the internal reflection at boundaries of the lens [8].…”

Section: Introductionmentioning

confidence: 99%

Microfabrication of electrode patterns for high-frequency ultrasound transducer arrays

Bernassau

Garcia‐Gancedo

Hutson

et al. 2012

IEEE Trans. Ultrason., Ferroelect., Freq. Contr.

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High-frequency ultrasound is needed for medical imaging with high spatial resolution. A key issue in the development of ultrasound imaging arrays to operate at high frequencies (≥30 MHz) is the need for photolithographic patterning of array electrodes. To achieve this directly on 1-3 piezocomposite, the material requires not only planar, parallel, and smooth surfaces, but also an epoxy composite filler that is resistant to chemicals, heat, and vacuum. This paper reports, first, on the surface finishing of 1-3 piezocomposite materials by lapping and polishing. Excellent surface flatness has been obtained, with an average surface roughness of materials as low as 3 nm and step heights between ceramic/polymer of ∼80 nm. Subsequently, high-frequency array elements were patterned directly on top of these surfaces using a photolithography process. A 30-MHz linear array electrode pattern with 50-μm element pitch has been patterned on the lapped and polished surface of a high-frequency 1-3 piezocomposite. Excellent electrode edge definition and electrical contact to the composite were obtained. The composite has been lapped to a final thickness of ∼55 μm. Good adhesion of electrodes on the piezocomposite has been achieved and electrical impedance measurements have demonstrated their basic functionality. The array was then packaged, and acoustic pulse-echo measurements were performed. These results demonstrate that direct patterning of electrodes by photolithography on 1-3 piezocomposite is feasible for fabrication of high-frequency ultrasound arrays. Furthermore, this method is more conducive to mass production than other reported array fabrication techniques.

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Fabrication of curved ceramic/polymer composite transducer for ultrasonic imaging applications by fused deposition of ceramics

Cited by 8 publications

References 8 publications

Fabrication and performance of high-frequency composite transducers with triangular-pillar geometry

Fabrication and performance of high-frequency composite transducers with triangular-pillar geometry

Dual-Frequency Piezoelectric Transducers for Contrast Enhanced Ultrasound Imaging

Microfabrication of electrode patterns for high-frequency ultrasound transducer arrays

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