Piezoelectric device

A piezoelectric device to be adopted for a microphone or a speaker, comprising:

• a beam portion including a piezoelectric layer made of a piezoelectric material, having a plate shape perpendicular to an axial direction of a directional axis of the piezoelectric device, and having a fixed end provided on one side of the beam portion in a first direction perpendicular to the axial direction, a free end provided on an opposite side of the beam portion in the first direction, one surface provided on one side of the beam portion in the axial direction, and an opposite surface provided on an opposite side of the beam portion in the axial direction, the beam portion configured as a cantilever beam in which the free end is capable of reciprocating displacement in the axial direction with respect to the fixed end;
• and
• a support portion to which the fixed end of the beam portion is fixed and which supports the fixed end, wherein
• the beam portion includes a concave and convex structure portion having at least one of a first concave and convex part and a second concave and convex part,
• the first concave and convex part has a first concave provided on the one surface and extending linearly in a second direction perpendicular to the axial direction and the first direction, and a first convex provided on the opposite surface at a portion overlapping the first concave on the opposite side in the axial direction and extending linearly in the second direction, and
• the second concave and convex part has a second convex provided on the one surface and extending linearly in the second direction, and a second concave provided on the opposite surface at a portion overlapping the second convex on the opposite side in the axial direction and extending linearly in the second direction.