Methods of making composite ultrasonic transducers

DETAILED DESCRIPTION Therefore, it is an object of the invention to provide a reliable and not excessively expensive process for producing multiple-element ultrasonic transducers, wherein each transducer element comprises a number of acoustic emitters separated from one other in one or two dimensions by a polymer matrix, and where each emitter itself comprises a stack of individual ceramic members, each provided with electrical connections such that the members of the elements can be connected in parallel and simultaneously excited.
It is therefore a further object of the invention to provide an improved ultrasonic transducer wherein each element comprises a number of emitters spaced from one another by a polymer matrix, and wherein each emitter in turn comprises a column of stacked ceramic members adapted to be connected electrically in parallel.
It is a further object of this invention to provide a transducer comprising layered composite emitters in a polymer matrix, having inter-layer electrodes which are not continuous planar members, thus substantially reducing the amount of metallic electrode material in the composite with respect to composites according to the prior art.
Furthermore, it is an object of the invention to provide an ultrasonic transducer that can resist high temperatures and humidity, so as to be rapidly sterilizable by conventional steam autoclaving techniques.
The present invention provides an improved transducer and elements therefor and a method of making these elements which is more reliable and less expensive then that shown in the Smith patents and other prior art referred to above.
A number of planar precursors, each comprising elongated strips of ceramic material separated from one another by a polymer material, are stacked one above another so that the elongated ceramic strips are aligned with one another, with planar electrical conductors disposed between and bonded to each of the opposed planar precursors.
The stack of precursors are then bonded to one another, forming a bonded assembly