Method for making multi-layer ceramic acoustic transducer

DETAILED DESCRIPTION OF THE INVENTION The invention is directed to a method for preparing a multi-layer ceramic acoustic stack comprised of an even number of ceramic layers.
For the purpose of illustration, a method for preparing a two-layer ceramic acoustic stack will now be disclosed in detail.
Two-layer stacks can themselves be stacked to construct multilayer stacks having four or more ceramic layers.
The disclosed method is useful for preparing acoustic elements in both linear and multi-row acoustic arrays, as well as small elements for two-dimensional acoustic arrays.
Such acoustic arrays are useful for medical imaging applications.
In accordance with the method for forming two-layer piezoelectric acoustic transducers disclosed in detail hereinafter, the structural integrity of the piezoelectric element is not weakened by removal of a portion of the element.
The method is based on laminating two piezoelectric ceramic layers with confronting metallized surfaces.
Optionally, a thin electrical conductor may be sandwiched between the metallized surfaces, i.
e.
, in the center.
The ceramic layers may be in the forms of bars of ceramic, or preferably, in the form of sheets or plates of ceramic.
In the latter case, following lamination to a center electrically conductive material, the material is diced into bars and rotated to expose the center electrically conducting material.
The bars are rotated 90 degrees to a position in which the center electrically conducting material is in a vertical position with respect to a surface.
In this position, the bars are laminated together.
The aligned surfaces on one face of the laminated structure are then coated with a dielectric material to electrically insulate the center electrically conducting material from a subsequent electrode.
Dielectric materials can be selected from common electrical insulators, including, but not limited to, parylene, polyimide, polyamideimide, polyurethane, and other materials, and can be applied by coating, dipping, lamination, or vapor deposition