A Two Dimensional PVDF Transducer Matrix as a Receiver in an Ultrasonic Transmission Camera

Abstract

A two dimensional ultrasonic receiver matrix with the piezoelectric polymer PVDF has been developed and tested in an ultrasonic transmission camera. The major advantage of this matrix over know receiver devices for ultrasonic cameras is its high sensitivity along with high bandwidth, its large number of small receiver elements and its pure electronic read-out. No mechanical moving of either the image or the receiver array is needed. The matrix read — out is realized by a stack of 29 thin film substrates with 128 switchable preamplifiers each. One side of the stack forms a contact matrix with 29 * 128 metal contacts of the size 0.75 mm * 0.65 mm, covering a total area of 26 mm * 96 mm. The contact matrix is pressed against a common 25 um PVDF foil as a common transducer. A parallel signal procession results in a homogenous image presentation. Transmission image of technical and biological objects with a frame rate of 25 Hz and a sensitivity of 6 * 10−6 V/Pa are sown. The intrinsic resolution of the camera — 1.7 mm at 2 MHz is reproduced in the image.