US 2007/0176711 A1Published application

Elastic boundary wave device

AssigneeMurata Manufacturing Co., Ltd.

InventorHajime Kando

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Abstract

An elastic boundary wave device includes an IDT including laminated conductor layers disposed between a first medium and a second medium, wherein a plane that divides the IDT in half in the thickness direction defines an interface, the energy of an elastic boundary wave present on the side of the first medium of the interface is denoted as E1, and the energy of an elastic boundary wave present on the side of the second medium of the interface is denoted as E2, and wherein if the IDT included only a conductor having the highest density among the laminated conductor layers of the IDT, when the energy of an elastic boundary wave present on the side of the first medium of the interface is denoted as E1′ and the energy of an elastic boundary wave present on the side of the second medium of the interface is denoted as E2′, the energies of an elastic boundary wave would satisfy the relationship of E1/E2<E1′/E2′ so that the sonic velocity of an elastic boundary wave in the IDT including the laminated conductor layers is equal to the sonic velocity of an elastic boundary wave if the IDT included only the conductor layer having the highest density.

Claims22

Dependent claims

An elastic boundary wave device comprising:

a first medium having a positive temperature coefficient of delay in a propagation direction of an elastic boundary wave;
a second medium having a negative temperature coefficient of delay in a propagation direction of an elastic boundary wave;
and
an IDT including laminated conductor layers disposed between the first medium and the second medium;
wherein
a lamination direction of the first medium and the second medium is the thickness direction of the IDT, a plane that divides the IDT in half in the thickness direction defines an interface, energy of an elastic boundary wave present on the first medium side of the interface is denoted as E1, and energy of an elastic boundary wave present on the second medium side of the interface is denoted as E2;
and
if the IDT included only of a conductor layer of a single metal having the highest density among the laminated conductor layers of the IDT, when the energy of an elastic boundary wave present on the first medium side of the interface is denoted as E1′ and the energy of an elastic boundary wave present on the second medium side of the interface is denoted as E2′, the energies of an elastic boundary wave would satisfy the relationship of E1/E2<E1′/E2′ so that the sonic velocity of an elastic boundary wave in the IDT including the laminated conductor layers is equal to the sonic velocity of an elastic boundary wave if the IDT included only of the conductor layer having the highest density.

5 more elements

Dependencies are inferred from the claim text.