Acoustic wave device
AssigneeMurata Manufacturing Co., Ltd.
InventorShou Nagatomo
Life of this patent
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Abstract
An acoustic wave device includes a support substrate, an acoustic reflection film on the support substrate, a piezoelectric layer on the acoustic reflection film, the piezoelectric layer including first and second primary surfaces, and first and second flat-plate electrodes on the first and second primary surfaces of the piezoelectric layer. The acoustic reflection film includes high acoustic impedance layers and low acoustic impedance layers alternately stacked together. At least one layer of the high acoustic impedance and low acoustic impedance layers is a stack of layers of first and second materials having equal or substantially equal acoustic impedances for at least one of longitudinal acoustic impedance and transversal acoustic impedance. The interface between the layers of first and second materials has irregularities.
Claims16
An acoustic wave device comprising:
- a support substrate;
- an acoustic reflection film on the support substrate;
- a piezoelectric layer on the acoustic reflection film, the piezoelectric layer including a first primary surface and a second primary surface opposite to each other;
- and
- at least one excitation electrode on at least one of the first and second primary surfaces of the piezoelectric layer;
- wherein
- the acoustic reflection film includes at least one high acoustic impedance layer, which has a relatively high acoustic impedance, and at least one low acoustic impedance layer, which has a relatively low acoustic impedance, the high and low acoustic impedance layers being alternately stacked together;
- at least one layer of the high acoustic impedance and low acoustic impedance layers is a stack of a layer of a first material and a layer of a second material, the first and second materials having equal or substantially equal acoustic impedances for at least one of longitudinal acoustic impedance and transversal acoustic impedance;
- and
- an interface between the layers of the first and second materials includes irregularities.
Dependencies are inferred from the claim text.