An Acoustic Image Sensor Using a Transmit-Receive Array

Abstract

A preliminary model of a novel acoustic image sensor which utilizes a multiplexed area array of transducers operating in a transmit-receive mode has been developed. The major components of the system include: 1) an acoustic lens for focusing the transmitted energy of an array element on the corresponding object element, 2) an area or two-dimensional array of acoustic transducers formed within a monolithic wafer of piezoelectric ceramic material; 3) an array of silicon monolithic integrated circuits located immediately adjacent to the piezoelectric array; each integrated circuit performs the transmit/receive multiplexing for several transducer array elements; 4) an analogue signal processor consisting of high power transmit circuitry as well as sensitive receiver circuitry including preamplifiers, swept gain amplifiers and function generators, filters, gain compressors and detectors; 5) a digital controller which permits a) any single array element or any row or column of array elements to operate in the A-scan mode, b) any row or column of array elements to operate in the B-scan mode or c) the full array of elements to operate in the C-scan mode; and 6) a display subsystem consisting of a cathode ray display and interface circuitry which provides an M-scan mode and interpolation in the C-scan mode. The image sensor operates at an acoustic frequency of 3.5 MHz and is intended for use in medical diagnostics.