Patent ID: 8963403
Filing Date: 2015-02-24
Classification: H03H

Abstract:
1. A piezoelectric device comprising: a substrate; at least two common layers; and at least one specific layer, the at least two common layers and the at least one specific layer being laminated on the substrate; wherein the at least two common layers and the at least one specific layer are arranged such that only a single piezoelectric material layer is sandwiched between a pair of electrodes including a lower electrode layer and an upper electrode layer, and at least first, second, and third vibration regions are provided in which the pair of electrodes are superimposed with the single piezoelectric material layer therebetween when viewed in a direction in which the at least two common layers and the at least one specific layer are laminated; the first, second, and third vibration regions are acoustically isolated from the substrate; the at least one specific layer includes a first portion having a first thickness and a second portion having a second thickness that is smaller than the first thickness, a ratio of the first portion to the second portion is different among the first, second, and third vibration regions; resonators including the corresponding first, second, and third vibration regions have different resonant frequencies; each of the at least two common layers has substantially the same structure in each of the first, second, and third vibration regions; the at least one specific layer has a different structure in each of the first, second, and third vibration regions; and at least two of the first, second, and third vibration regions share one common air gap defined by a recessed portion of the substrate.