Ultrasonic cmut with suppressed acoustic coupling to the substrate

Abstract

An array of cMUT cells are formed on individually isolated massive plates on a substrate. The mass of each plate provides an inertial force in opposition to the force and motion of transmission by the cell which reduces the resultant translation of motion in the plate. The reduction in motion results in less coupling of acoustic energy into the substrate and contamination of the signals of adjacent cMUT cells by lateral waves. The unwanted wave coupling into the substrate can be further damped by compliant or sparse periodic mounting of the massive plates on the substrate.

Description

technical field [0001] The present invention relates to medical diagnostic ultrasound systems and, in particular, to cMUT arrays with suppressed acoustic coupling of reverberant energy to the substrate of the cMUT (Capacitive Micromachined Ultrasound Transducer) array. Background technique [0002] MUTs, especially cMUTs, are ultrasonic transducer elements fabricated by semiconductor manufacturing techniques. Unlike conventional piezoelectric materials such as PZT, MUTs can operate through effects other than strictly piezoelectric. In the case of a cMUT, the diaphragm is vibrated in the manner of the diaphragm of a drum by the variable capacitance effect. Vibration of the diaphragm produces emitted ultrasonic energy. When receiving, the diaphragm is vibrated by the returned echo, and the capacitance change is sensed to detect the received echo signal. In my US patent 6328697 the figure 1 A typical cMUT cell is shown in . in this patent figure 2 An electrical diagram f...

AI Technical Summary

Problems solved by technology

These issues have contributed to the lack of commercial acceptance of cMUTs in the field of medical imaging

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