ACOUSTIC PROPERTIES OF LENS MATERIALS FOR ULTRASONIC PROBES

The acoustic velocities and densities of 20 types of commercial rubber have been measured at a frequency of 2 MHz at room temperature, and t hey are evaluated in terms of their application to an acoustic lens or an acoustic window of probes of an ultrasonic diagnostic instrument. Fluorosilicone rubber and phosphazene rubber have lower acoustic veloc ities than the human body, and they have excellent impedance matching with the human body. Both the acoustic velocities and densities of but adiene rubber, polybutadiene rubber, acrylic rubber and polyurethane m atch those of the human body. It is also described that rubber having good impedance matching with the human body can be fabricated by adjus ting the volume fraction of the added filler.