Piezoelectric resonator

A piezoelectric resonator comprising:

• a piezoelectric member and an excitation electrode that overlap with each other in a thickness direction,
• wherein the piezoelectric member has a high acoustic velocity region and a low acoustic velocity region in which an acoustic velocity is lower than an acoustic velocity in the high acoustic velocity region,
• in a plan view in the thickness direction, the high acoustic velocity region overlaps a center portion of the excitation electrode, and the low acoustic velocity region overlaps an end portion of the excitation electrode,
• the excitation electrode includes a plurality of holes in the high acoustic velocity region such that a mass per unit area of the high acoustic velocity region is smaller than a mass per unit area of the low acoustic velocity region,
• in a first direction intersecting the thickness direction, a dimension of a portion of the low acoustic velocity region that is adjacent to the high acoustic velocity region in the first direction is smaller than a dimension of the high acoustic velocity region in the first direction, and
• in the plan view in the thickness direction, an area of the low acoustic velocity region is smaller than an area of the high acoustic velocity region.