Shock-hardened, high pressure ceramic sonar transducer

Claim 1

A shock-hardened high pressure sonar transducer comprising: a housing made from a first material having an open front, said housing being capable of withstanding high pressures and severe mechanical shock without damage resulting thereto; a flexible cover sealed over and around said open front thereby creating a sealed-over front of said housing; a fluid disposed inside of said housing for coupling pressures throughout the inside of said housing, said fluid being inserted into said housing under pressure; acoustic impedance mismatch means selectively placed on the inside of said housing for causing said transducer to assume a desired directivity pattern wherein substantially all of the sonar signals associated with the operation of said transducer must be received or transmitted through the sealed-over front of said housing; protection means for shielding said acoustic impedance mismatch means from direct contact with said pressurized fluid; and transducer means mounted inside said housing for sensing and generating sonar signals, said transducer means comprising a plurality of piezoelectric stacks, each having front and rear ends, and each adapted to undergo a dimensional change when stressed electrically and to generate an electrical signal when stressed mechanically; a single front mass attached directly to the front ends of each of said stacks; respective rear masses attached directly to the rear ends of each of said stacks; means for allowing said pressurized fluid to flow around and inside of said stacks; means for making electrical contact with said stacks, said means adapted to allow external electrical signals to electrically stress said stacks and to further allow electrical signals generated by mechanical stress of said stacks to be externally sensed.