Patent ID: 6013311
Filing Date: 2000-01-11
Classification: H01L,H04R,Y10T

Abstract:
A method of forming a piezoelectric element which includes piezoelectric material having a variable functionally gradient d.sub.31 coefficient comprising coating a block having a uniform concentration of piezoelectric material with a predetermined porosity by the steps of:(a) applying a first layer having piezoelectric material with a same or different first chemical composition than the block onto a surface of the block and processing such first layer to have a different porosity than the predetermined porosity which is selected so as to provide a different morphological structure than the block, by dip coating the first layer from a bath containing an aqueous slurry of piezoelectric material of the first chemical composition;(b) applying a second layer of piezoelectric material, by dip coating the second layer from a bath containing an aqueous slurry of piezoelectric material of the first chemical composition on the first layer with the same or different first chemical composition of piezoelectric material than the block and processing such second layer to have a different porosity than the previously deposited first layer so as to provide a different morphological structure than the block;(c) applying heat to the block and the first and second applied layers to dry the first and second applied layers; and(d) then applying heat to sinter the piezoelectric block and first and second applied layers so as to form a piezoelectric element with a functionally gradient d.sub.31 coefficient.