Capacitive micromachined ultrasonic transducers for medical imaging and therapy

Khuri‐Yakub, Butrus T.; Oralkan, Ömer

doi:10.1088/0960-1317/21/5/054004

Cited by 260 publications

(134 citation statements)

References 51 publications

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“…However, ultrasonic fingerprint sensors previously provided a low resolution or were too difficult to manufacture. With the rapid development of microelectromechanical systems (MEMS) technology, micromachined ultrasonic transducers (MUTs) based on capacitive (CMUT) and piezoelectric (PMUT) transduction have been demonstrated with significantly reduced device sizes for high-resolution applications, low power consumption and better acoustic impedance matching to the medium 1,2 . In general, CMUTs suffer from limited vertical deformation, nonlinear drive effects and high DC bias voltages, but they have high electromechanical coupling factors 3 .…”

Section: Introductionmentioning

confidence: 99%

Monolithic ultrasound fingerprint sensor

et al. 2017

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This paper presents a 591 × 438-DPI ultrasonic fingerprint sensor. The sensor is based on a piezoelectric micromachined ultrasonic transducer (PMUT) array that is bonded at wafer-level to complementary metal oxide semiconductor (CMOS) signal processing electronics to produce a pulse-echo ultrasonic imager on a chip. To meet the 500-DPI standard for consumer fingerprint sensors, the PMUT pitch was reduced by approximately a factor of two relative to an earlier design. We conducted a systematic design study of the individual PMUT and array to achieve this scaling while maintaining a high fill-factor. The resulting 110 × 56-PMUT array, composed of 30 × 43-μm 2 rectangular PMUTs, achieved a 51.7% fill-factor, three times greater than that of the previous design. Together with the custom CMOS ASIC, the sensor achieves 2 mV kPa − 1 sensitivity, 15 kPa pressure output, 75 μm lateral resolution, and 150 μm axial resolution in a 4.6 mm × 3.2 mm image. To the best of our knowledge, we have demonstrated the first MEMS ultrasonic fingerprint sensor capable of imaging epidermis and sub-surface layer fingerprints. INTRODUCTIONFingerprint sensors capture an electronic image of a human fingerprint through various physical mechanisms, including optical, capacitive, pressure and acoustic mechanisms. Capacitive fingerprint sensors are the standard for identity authentication in numerous applications because of their performance and low cost; the latter is due to the fact that these sensors can be manufactured in a standard integrated circuit manufacturing process. Ultrasonic fingerprint sensors have many advantages over capacitive sensors, including being insensitive to contamination and moisture on the finger. In addition, ultrasonic waves used in pulse-echo imaging can penetrate the finger's epidermis, collecting images of sub-surface features. However, ultrasonic fingerprint sensors previously provided a low resolution or were too difficult to manufacture. With the rapid development of microelectromechanical systems (MEMS) technology, micromachined ultrasonic transducers (MUTs) based on capacitive (CMUT) and piezoelectric (PMUT) transduction have been demonstrated with significantly reduced device sizes for high-resolution applications, low power consumption and better acoustic impedance matching to the medium

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Section: Introductionmentioning

confidence: 99%

Monolithic ultrasound fingerprint sensor

et al. 2017

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“…Experiments are conducted with three different target diameters and four different eccentricities to verify its feasibility. The dimension error is limited to 0.043 mm 2 or 0.42% in area. The positioning error is 0.052 mm for target dimeter of 3.6 mm and eccentricity of 1.2 mm.…”

Section: Discussionmentioning

confidence: 99%

“…Haller and Khuri-Yakub developed the first capacitive micromachined ultrasonic transducer using silicon-based semiconductor technology [1]. The CMUT has advantages of miniaturization of devices, wide bandwidth, and high intensity focused ultrasound [2]. Later, Chang et al introduced the first polymer-based CMUT using SU-8 photoresist for surgical imaging applications [3].…”

Section: Introductionmentioning

confidence: 99%

Research on the Measuring System of Polymer-based Capacitive Micromachined Ultrasonic Transducer Array for Circular Planar Target

Bui¹,

Chiang²,

Pang³

2017

Proceedings of the Second International Conference on Mechanics, Materials and Structural Engineering (ICMMSE 2017)

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Abstract. The purpose of this research is using a polymer-based capacitive micro-machined ultrasonic transducer (CMUT) array to determine the position and dimension of circular planar target. The polymer-based CMUT is consist of an indium tin oxide-polyethylene terephthalate (ITO-PET) substrate and SU-8 sidewall and vibrating membranes. The CMUT has advantages of flexibility, low cost and large sensing area application comparing with silicon-based sensor. A fourquadrant (4Q) array is used to determine the position of the circular target based on the time of flight (TOF) and magnitude of the acoustic echo signals reflected from the target. The measuring system is designed to determine diameter and position of the transparent objects for pick and place on a conveyor. The four quadrant array has an overall dimension of 6 mm × 6 mm and can detect target diameter up to 3.6 mm with a maximum eccentricity of 1.2 mm. An algorithm is proposed to correct nonlinearity error when the target is away from the center of the four-quadrant array. The ultrasonic measuring system is constructed and tested to demonstrate its feasibility. The experimental results show the position error of 0.052 mm and dimension error of 0.42% in area at the worst scenario.

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“…Therefore, we use CMUTs to improve the definition of fine structures within the arteries. Specifically, a 128-element linear CMUT array will be a suitable compromise between resolution and manufacturing cost [13]. Two independent arrays are placed on the neck to simultaneously monitor both carotid arteries, as shown in Fig.…”

Section: System Designmentioning

confidence: 99%

A wearable carotid ultrasound assembly for early detection of cardiovascular diseases

Shomaji

Basak

Mandai

et al. 2016

2016 IEEE Healthcare Innovation Point-of-Care Technologies Conference (HI-POCT)

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Abstract-Cardiovascular disease is currently responsible for a major portion of all global deaths. Fortunately, early detection of its symptoms can greatly contribute to effective prevention. Hence, clinicians recommend routine cardiovascular check-ups. Even though various methods for cardiac diagnosis exist, most of them are clinic-based, and therefore time-consuming and costly. Therefore, it is not always possible for patients to go through these procedures on a regular basis. In this paper, we propose a novel wearable ultrasonic imaging assembly for routine, easy-to-use, and economical monitoring of the carotid arteries. The device monitors intima-media thickness (IMT), which is a proven clinically useful marker for diagnosis of cardiovascular disease and prediction of imminent cardiovascular events. It uses standard B-mode ultrasound, which is suitable for implementation within area-and power-constrained wearable form factors. We present design parameters and power requirements for all the essential hardware components of the proposed wearable imaging system. We also present an efficient algorithm for predicting IMT anomalies from ultrasound images.

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Capacitive micromachined ultrasonic transducers for medical imaging and therapy

Cited by 260 publications

References 51 publications

Monolithic ultrasound fingerprint sensor

Monolithic ultrasound fingerprint sensor

Research on the Measuring System of Polymer-based Capacitive Micromachined Ultrasonic Transducer Array for Circular Planar Target

A wearable carotid ultrasound assembly for early detection of cardiovascular diseases

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