Air-coupled ultrasound transduction improvement using vertical piezoelements’ array

IF 4.9 3区工程技术 Q2 ENGINEERING, ELECTRICAL & ELECTRONIC

Sensors and Actuators A-physical Pub Date : 2025-10-17 DOI:10.1016/j.sna.2025.117178

Linas Svilainis , Valdas Eidukynas , Luca De Marchi , Andrius Chaziachmetovas

{"title":"Air-coupled ultrasound transduction improvement using vertical piezoelements’ array","authors":"Linas Svilainis , Valdas Eidukynas , Luca De Marchi , Andrius Chaziachmetovas","doi":"10.1016/j.sna.2025.117178","DOIUrl":null,"url":null,"abstract":"<div><div>Novel transducer construction is proposed: array of PVDF film strips placed parallel to each other with air gaps between. Films are oriented in such way that strip extension (31 mode) is aligned with emission direction. Transduction is improved by providing better acoustic impedance match to air and increased displacement of emitting surface. Two distinct operation modes are presented: i) emission from the gaps ii) emission from membrane attached to the edges at array top with lower edges backed.</div><div>In gap emission mode, the transduction efficiency is increased because of two mechanisms. The pressure produced by the expansion of the individual films is concentrated into narrow gap. Also, emission of edges due to height extension. Height extension (31 mode) is much higher than thickness expansion (33 mode) if film height is larger than film thickness. Low, 500 Rayl, equivalent acoustic impedance of gap emission is achieved at film thickness 10 μm and gap with 50 μm.</div><div>In membrane emission mode, only extension (31 mode) is used, pressure emitted is increased due to large membrane displacement and better match to air. Equivalent acoustic impedance is 500 kRayl at PVDF film thickness 40 μm and 200 μm air gap. Displacement is maximized if PVDF film with large transverse piezoelectric coefficient d<sub>31</sub> is used.</div><div>Experimental measurements are presented. Transmission sensitivity peak for gap emission was 155 mPa/V, for membrane emission mode it was 320 mPa/V. Impressive, more than 270 % fractional bandwidth was confirmed experimentally.</div></div>","PeriodicalId":21689,"journal":{"name":"Sensors and Actuators A-physical","volume":"396 ","pages":"Article 117178"},"PeriodicalIF":4.9000,"publicationDate":"2025-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Sensors and Actuators A-physical","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0924424725009847","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENGINEERING, ELECTRICAL & ELECTRONIC","Score":null,"Total":0}

引用次数: 0

Abstract

Novel transducer construction is proposed: array of PVDF film strips placed parallel to each other with air gaps between. Films are oriented in such way that strip extension (31 mode) is aligned with emission direction. Transduction is improved by providing better acoustic impedance match to air and increased displacement of emitting surface. Two distinct operation modes are presented: i) emission from the gaps ii) emission from membrane attached to the edges at array top with lower edges backed.

In gap emission mode, the transduction efficiency is increased because of two mechanisms. The pressure produced by the expansion of the individual films is concentrated into narrow gap. Also, emission of edges due to height extension. Height extension (31 mode) is much higher than thickness expansion (33 mode) if film height is larger than film thickness. Low, 500 Rayl, equivalent acoustic impedance of gap emission is achieved at film thickness 10 μm and gap with 50 μm.

In membrane emission mode, only extension (31 mode) is used, pressure emitted is increased due to large membrane displacement and better match to air. Equivalent acoustic impedance is 500 kRayl at PVDF film thickness 40 μm and 200 μm air gap. Displacement is maximized if PVDF film with large transverse piezoelectric coefficient d₃₁ is used.

Experimental measurements are presented. Transmission sensitivity peak for gap emission was 155 mPa/V, for membrane emission mode it was 320 mPa/V. Impressive, more than 270 % fractional bandwidth was confirmed experimentally.

查看原文本刊更多论文

利用垂直压电元件阵列改进空气耦合超声转导

提出了一种新颖的换能器结构：PVDF薄膜条阵列彼此平行放置，中间有气隙。薄膜以这样的方式取向，使得条带延伸（31模式）与发射方向对齐。通过提供更好的与空气匹配的声阻抗和增加发射面位移来改善转导。提出了两种不同的工作模式：1)从间隙发射；2)从附着在阵列顶部边缘上的膜发射。在间隙发射模式下，由于两种机制的作用，转导效率得以提高。单个薄膜膨胀产生的压力被集中到狭窄的间隙中。此外，由于高度扩展而产生的边缘发射。当膜高大于膜厚时，高度扩展（31模式）远高于厚度扩展（33模式）。在膜厚为10 μm和隙厚为50 μm时，实现了低至500 Rayl的等效声阻抗。膜发射模式下，只使用延伸（31模式），由于膜位移大，发射压力增加，与空气匹配更好。当PVDF膜厚为40 μm，气隙为200 μm时，等效声阻抗为500 kRayl。采用横向压电系数d31较大的PVDF薄膜时，位移最大。给出了实验测量结果。间隙发射的透射灵敏度峰值为155 mPa/V，膜发射的透射灵敏度峰值为320 mPa/V。令人印象深刻的是，超过270 %的分数带宽被实验证实。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

来源期刊

Sensors and Actuators A-physical 工程技术-工程：电子与电气

CiteScore

8.10

自引率

6.50%

发文量

630

审稿时长

49 days

期刊介绍： Sensors and Actuators A: Physical brings together multidisciplinary interests in one journal entirely devoted to disseminating information on all aspects of research and development of solid-state devices for transducing physical signals. Sensors and Actuators A: Physical regularly publishes original papers, letters to the Editors and from time to time invited review articles within the following device areas: • Fundamentals and Physics, such as: classification of effects, physical effects, measurement theory, modelling of sensors, measurement standards, measurement errors, units and constants, time and frequency measurement. Modeling papers should bring new modeling techniques to the field and be supported by experimental results. • Materials and their Processing, such as: piezoelectric materials, polymers, metal oxides, III-V and II-VI semiconductors, thick and thin films, optical glass fibres, amorphous, polycrystalline and monocrystalline silicon. • Optoelectronic sensors, such as: photovoltaic diodes, photoconductors, photodiodes, phototransistors, positron-sensitive photodetectors, optoisolators, photodiode arrays, charge-coupled devices, light-emitting diodes, injection lasers and liquid-crystal displays. • Mechanical sensors, such as: metallic, thin-film and semiconductor strain gauges, diffused silicon pressure sensors, silicon accelerometers, solid-state displacement transducers, piezo junction devices, piezoelectric field-effect transducers (PiFETs), tunnel-diode strain sensors, surface acoustic wave devices, silicon micromechanical switches, solid-state flow meters and electronic flow controllers. Etc...