Development of 40-MHz Ultrasonic Transducers via Soft Mold Process

Gunther, Paul; Neumeister, Peter; Neubert, Holger; Gebhardt, Sylvia

doi:10.1109/tuffc.2019.2923554

Cited by 8 publications

(4 citation statements)

References 12 publications

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“…Fabrication of a high frequency transducer (>30 MHz) is particularly challenging considering the design requirements described above. Various processing methods have been developed to fabricate composite ultrasound transducers such as align-and-fill [27], diceand-fill [28][29][30], injection molding [31], lost mold technique [32,33], tape lamination [34][35][36][37][38], laser or ultrasonic machining [39,40], coextrusion [41], jet-machining [42], deep reactive ion etching (DRIE) [43], and solid freeform fabrication (SFF) [44]. Among these techniques, dice-and-fill, injection molding, and lost mold techniques are popular for fabricating 2-2 composites for medical imaging applications [45][46][47].…”

Section: Processingmentioning

confidence: 99%

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Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

et al. 2021

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Medical ultrasound and other devices that require transducer arrays are difficult to manufacture, particularly for high frequency devices (>30 MHz). To enable focusing and beam steering, it is necessary to reduce the center-to-center element spacing to half of the acoustic wavelength. Conventional methodologies prevent co-sintering ceramic–polymer composites due to the low decomposition temperatures of the polymer. Moreover, for ultrasound transducer arrays exceeding 30 MHz, methods such as dice-and-fill cannot provide the dimensional tolerances required. Other techniques in which the ceramic is formed in the green state often fail to retain the required dimensions without distortion on firing the ceramic. This paper explores the use of the cold sintering process to produce dense lead zirconate titanate (PZT) ceramics for application in high frequency transducer arrays. PZT–polymer 2-2 composites were fabricated by cold sintering tape cast PZT with Pb nitrate as a sintering aid and ZnO as the sacrificial layer. PZT beams of 35 μm width with ~5.4 μm kerfs were produced by this technique. The ZnO sacrificial layer was also found to serve as a liquid phase sintering aid that led to grain growth in adjacent PZT. This composite produced resonance frequencies of >17 MHz.

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Section: Processingmentioning

confidence: 99%

“…This green body is then conventionally sintered to >98% relative density. Günther et al [32] adopted this technique to fabricate a 40 MHz transducer with pillar diameters as low as 30 µm with 10 µm spacing. However, when their diameter was reduced to 15 µm, the pillars were subject to deformation on firing.…”

Section: Processingmentioning

confidence: 99%

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

et al. 2021

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“…In addition, to obtain a higher axial and lateral resolution of echo US images, the thickness mode vibration (TMV) of transducers must be clean enough to avoid any spurious-mode vibrations (SMV). 38) Although the PMN-PT SC transducers are particularly suitable for commercial applications where a low signal-to-noise ratio is to be expected, large SMV responses near the fundamental TMV were still occasionally observed after poling, especially in the specific ACP process. 36) In practice, this issue leads to an unwanted signal-to-noise ratio, affecting the depth resolution of defects of the echo US images.…”

Section: Introductionmentioning

confidence: 99%

Dielectric, piezoelectric, and spurious mode vibration properties by four types of waveforms AC poling for Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ single crystals

Sun

Karaki

Wang

et al. 2021

Jpn. J. Appl. Phys.

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Four types of waveforms of AC poling (ACP) and DC poling (DCP) were applied on [001]-oriented 0.72Pb(Mg 1/3 Nb 2/3 )O 3 -0.28PbTiO 3 (PMN-28PT) ferroelectric single crystals (SCs) at 80 °C. High voltage (5 kV cm −1 ) ACP of all four waveforms and DCP SCs tend to show low piezoelectric coefficient (d 33 ) less than 1660 pC/N and large spurious-mode vibration (SMV) at the thickness mode vibration (TMV) on impedance spectrum. The highest d 33 of 1830 pC/N was obtained by a triangle wave of 3 kV cm −1 SCs with tiny SMV. By contrast, low voltage (1.5 kV cm −1 ) ACP SCs with sine and triangle waveforms showed high d 33 of 1750 pC/N and 1670 pC/N without any SMV. We consider that the SMV is more easily caused by the over-poling of PMN-28PT SC. This information will help realize high piezoelectric properties and high production yield for ACP PMN-PT SC transducers for high-resolution medical ultrasound imaging equipment. © 2021 The Japan Society of Applied Physics Experimental methodsThe [001] seeded PMN-PT SC was grown with one charge Bridgman (OC BM) method and [001]-oriented wafers were cut from the ingot. A piece of PMN-28PT wafer from the SC ingot was sliced to more than 100 rectangular plates of

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“…Using single-fibre piezocomposite instead of monolithic ceramics offers several advantages. Besides higher electro-mechanical coupling and lower acoustic impedance [11,12], the fibres can be arbitrary placed in the composite [13]. In addition, the round shape offers superior acoustic emission characteristics for our unfocused imaging approach [10].…”

Section: Introductionmentioning

confidence: 99%

Model-Guided Manufacturing of Transducer Arrays Based on Single-Fibre Piezocomposites

et al. 2020

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For breast cancer imaging, ultrasound computer tomography (USCT) is an emerging technology. To improve the image quality of our full 3-D system, a new transducer array system (TAS) design was previously proposed. This work presents a manufacturing approach which realises this new design. To monitor the transducer quality during production, the electro-mechanical impedance (EMI) was measured initially and after each assembly step. To evaluate the measured responses, an extended Krimholtz–Leedom–Matthaei (KLM) transducer model was used. The model aids in interpreting the measured responses and presents a useful tool for evaluating parasitic electric effects and attenuation at resonance. For quality control, the phase angle at thickness resonance φ t was found to be the most specific EMI property. It can be used to verify the functionality of the piezocomposites and allows reliable detection of faults in the acoustic backing. Evaluating the final response of 68 transducers showed 5% variance of the series resonance frequency. This indicates good consistency of derived ultrasound performance parameters.

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Development of 40-MHz Ultrasonic Transducers via Soft Mold Process

Cited by 8 publications

References 12 publications

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

Dielectric, piezoelectric, and spurious mode vibration properties by four types of waveforms AC poling for Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ single crystals

Model-Guided Manufacturing of Transducer Arrays Based on Single-Fibre Piezocomposites

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Development of 40-MHz Ultrasonic Transducers via Soft Mold Process

Cited by 8 publications

References 12 publications

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

Cold Sintering of PZT 2-2 Composites for High Frequency Ultrasound Transducer Arrays

Dielectric, piezoelectric, and spurious mode vibration properties by four types of waveforms AC poling for Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals

Model-Guided Manufacturing of Transducer Arrays Based on Single-Fibre Piezocomposites

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Dielectric, piezoelectric, and spurious mode vibration properties by four types of waveforms AC poling for Pb(Mg_1/3Nb_2/3)O₃-PbTiO₃ single crystals