Piezoelectric element and piezoelectric device

#1. Field of the Invention

#The present invention relates to a piezoelectric element and a piezoelectric device.

#2. Related Background Art

#FIG. 1 is an exploded perspective view illustrating a multilayer piezoelectric element according to a first embodiment.

#FIG. 2 is a schematic view illustrating a piezoelectric layer with individual electrodes formed thereon, in the multilayer piezoelectric element illustrated in FIG. 1.

#FIG. 3 is a schematic diagram illustrating a piezoelectric layer with a common electrode formed thereon, in the multilayer piezoelectric element illustrated in FIG. 1.

#The preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. The same elements, or elements with the same function will be denoted by the same reference symbols in the description, without redundant description. The terms “upper” and “lower” are used in the description, and they correspond to the vertical relation in each drawing.

#First, a configuration of a multilayer piezoelectric element according to the first embodiment will be described on the basis of FIGS. 1 to 7. FIG. 1 is an exploded perspective view illustrating the multilayer piezoelectric element of the present embodiment. FIG. 2 is a schematic diagram illustrating a piezoelectric layer with individual electrodes formed thereon, in the multilayer piezoelectric element illustrated in FIG. 1. FIGS. 3 and 4 are schematic diagrams illustrating piezoelectric layers with a common electrode formed thereon, in the multilayer piezoelectric element illustrated in FIG. 1. FIG. 5 is a schematic diagram illustrating a piezoelectric layer with external electrodes formed thereon, in the multilayer piezoelectric element illustrated in FIG. 1. FIG. 6 is a schematic diagram illustrating individual electrodes and a common electrode in the multilayer piezoelectric element illustrated in FIG. 1. FIG. 7 is a schematic diagram illustrating a sectional configuration of the multilayer piezoelectric element of the first embodiment.

#The multilayer piezoelectric element PE1 is provided with a multilayer body LA1 of rectangular parallelepiped shape. The multilayer body LA1, as shown in FIG. 1, is constructed of an alternate stack of piezoelectric layers 3 and piezoelectric layers 5 four each, and a piezoelectric layer 7 and a piezoelectric layer 9 (outermost piezoelectric layer) arranged to interpose the piezoelectric layers 3 and 5 in between from top and bottom. Individual electrodes 2 (first internal electrode) are formed on each of the piezoelectric layers 3. A common electrode 4 (second internal electrode) is formed on each of the piezoelectric layers 5. External electrodes 17, 18 are formed on the piezoelectric layer 7. A common electrode 19 (second internal electrode) is formed on the piezoelectric layer 9. The piezoelectric layer 9 constitutes one end face in a stack direction of the multilayer body LA1 (in the first embodiment the “stack direction of the multilayer body LA1” will be referred to hereinafter simply as “stack direction”). The piezoelectric layer 7 constitutes the other end face in the stack direction.