Stacked piezoelectric device

A stacked piezoelectric device including a ceramic laminate formed by laminating a plurality of piezoelectric ceramic layers and a plurality of inner electrode layers alternately and a pair of side electrodes formed on side surfaces extending in a direction perpendicular to a laminating direction of the ceramic laminate, characterized in that

• said inner electrode layers have a conductive inner electrode-formed area and an inner electrode-unformed area where an outer peripheral edge of said inner electrode-formed area is recessed inwardly from an outer peripheral surface of said ceramic laminate by a given recessed distance and are each connected electrically to one of said side electrodes alternately at the inner electrode-formed areas,
• said ceramic laminate has slit-like stress absorbing portions recessed inwardly from the side surfaces thereof to have given depths,
• if, in a cross section of the stacked piezoelectric device, as taken in the laminating direction, the stress absorbing portions connected to a negative side of the side electrodes are defined as negative electrode side absorbing portions, and one of two of the inner electrode layers interleaving the negative electrode side absorbing portion which is connected to the negative side of the side electrodes is defined as a reference electrode layer, the recessed distance of the inner electrode-unformed area of each of the inner electrode layers which is located next to the reference electrode layer, interleaves the reference electrode layer between itself and the negative electrode side absorbing portion in the laminating direction, and is connected to a positive side of the side electrodes is greater than the depths of the negative electrode side absorbing portions, and
• if, in the cross section of the stacked piezoelectric device in the laminating direction, the stress absorbing portions connected to a positive side of the side electrodes are defined as positive electrode side absorbing portions, of two of the inner electrode layers which are located next to and interleave the positive electrode side absorbing portion therebetween, the recessed distance of the inner electrode-unformed area of one connected to the negative side of the side electrodes is greater than the depths of the positive electrode side absorbing portions.

A stacked piezoelectric device including a ceramic laminate formed by laminating a plurality of piezoelectric ceramic layers and a plurality of inner electrode layers alternately and a pair of side electrodes formed on side surfaces extending in a direction perpendicular to a laminating direction of the ceramic laminate, characterized in that

• said inner electrode layers have a conductive inner electrode-formed area and an inner electrode-unformed area where an outer peripheral edge of said inner electrode-formed area is recessed inwardly from an outer peripheral surface of said ceramic laminate by a given recessed distance and are each connected electrically to one of said side electrodes alternately at the inner electrode-formed areas,
• said ceramic laminate has slit-like stress absorbing portions recessed inwardly from the side surfaces thereof to have given depths,
• if two of the inner electrode layers interleaving said stress absorbing portion therebetween are defined as adjacent electrode layers, in a cross section of the stacked piezoelectric device, as taken in the laminating direction, separation portions are provided which are each defined by an interval in a direction perpendicular to the laminating direction between said outer peripheral edge of the inner electrode-formed area of the adjacent layer and a top end of the stress absorbing portion located on the same side surface as the inner electrode-unformed portion of said adjacent layer.