Showing papers on "Non-contact ultrasound published in 1983"
TL;DR: The transducer is probably the single most important component of any ultrasonic imaging system and the techniques for modeling the electromechanical impulse response are reviewed, with emphasis on the spatio-temporal impulse response technique.
Abstract: The transducer is probably the single most important component of any ultrasonic imaging system. A basic introduction to the problems and paradoxes of transducer design is given. After introducing the piezoelectric equations and discussing important transducer material such as lead zirconate titanate and polyvinylidene difluoride, the techniques for modeling the electromechanical impulse response are reviewed. Quarter-wave matching and short pulse techniques are discussed. The prediction of the ultrasound field of plane, spherical, and conical transducers is reviewed with emphasis on the spatio-temporal impulse response technique. Finally, the use of the above approaches is illustrated in a very practical fashion for three interesting transducer geometries: 1) a split aperture device with two focal lengths, 2) a five-element annular array, and 3) a 37.5 degree conical/annular array hybrid transducer.
232 citations
TL;DR: In this article, the use of various glues, varnishes and resins for the ultrasound absorbing coating is considered and the rate of temperature rise over the first one or two hundred milliseconds after the ultrasound is switched on is a reasonably linear function of intensity over the range used in physiotherapy.
76 citations
01 Jan 1983
TL;DR: In this article, the design of an under liquid transducer which is based upon electromagnetic acoustic operation is described, and the results of trials in water are presented and these show a high signal to noise ratio.
Abstract: There are hostile environments which are unsuitable for standard piezoelectric transducers. For example, liquids at temperatures in excess of the piezoelement Curie Temperature or situations with a high radiation level. An electromagnetic acoustic transducer has component parts which are considerably less sensitive to such influences.
This paper describes the design of an under liquid transducer which is based upon electromagnetic acoustic operation. The transducer embodies Rayleigh wave generation and mode conversion. The results of trials in water are presented and these show a high signal to noise ratio.
2 citations