Experimental Investigation of Inter-element Isolation in a Medical Array Transducer at Various Manufacturing Stages. (January 2017)

• Record Type: Journal Article
• Authors: Marinozzi, Franco; Bini, Fabiano; Grandoni, Andrea
• Is Part Of: Ultrasonic imaging. Volume 39:Number 1(2017)
• Page Start: 62
• Page End: 74
• Publication Date: 2017-01
• Subjects: array transducers -- inter-element cross-coupling -- laser Doppler vibrometry -- manufacturing process; Diagnostic ultrasonic imaging -- Methodology -- Periodicals; Ultrasonic testing -- Periodicals; Ultrasonic imaging -- Periodicals; Ultrasonography -- Periodicals; Échographie -- Méthodologie -- Périodiques; Essais par ultrasons -- Périodiques; Imagerie ultrasonore -- Périodiques; 616.07543
• DOI: 10.1177/0161734615595351
• Languages: English
• ISSNs: 0161-7346

Abstract

This work presents the experimental investigation of vibration maps of a linear array transducer with 192 piezoelements by means of a laser Doppler vibrometer at various manufacturing finishing steps in air and in water. Over the years, many researchers have investigated cross-coupling in fabricated prototypes but not in arrays at various manufacturing stages. Only the central element of the array was driven at its working frequency of 5 MHz. The experimental results showed that the contributions of cross-coupling depend on the elements of the acoustic stack: Lead Zirconate Titanate (PZT), kerf, filler, matching layer, and lens. The oscillation amplitudes spanned from (6 ± 38%) nm to (110 ± 40%) nm when the energized element was tested in air and from (6 ± 57%) nm to (80 ± 67%) nm when measurements were obtained under water. The best inter-element isolation of −22 dB was measured in air after cutting the kerfs, whereas the poorest isolation was −2 dB under water with an acoustic lens (complete acoustic stack). The vibration pattern in water showed a higher standard deviation on the displacement measurements than the one obtained in air, due to the influence of acousto-optic interactions. The amount increased to 30% in water, as estimated by a comparison with the measurements in air. This work describes a valuable method for manufacturers to investigate the correspondence between the manufacturing process and the quantitative evaluations of the resulting effects.