Patent ID: 9503049
Filing Date: 2016-11-22
CPC Classification: H03H

Claim Text:
1. An acoustic wave element, comprising: a piezoelectric substrate; an electrode which is located on an upper surface of the piezoelectric substrate and which contains Al as a major component; a first film which is located on an upper surface of the electrode; and an insulation layer which covers the first film and a portion of the piezoelectric substrate which is exposed from the electrode, which has a thickness from the upper surface of the piezoelectric substrate which is larger than a total thickness of the electrode and the first film, and which contains a silicon oxide as a major component, wherein the first film contains as a major component a material which has a larger acoustic impedance than a material of the electrode and a material of the insulation layer and which has a slower propagation velocity of an acoustic wave than the material of the electrode and the material of the insulation layer, and wherein a normalized thickness t/λ of the first film is within a range of a following equation (A): where T/λ is a normalized thickness of the insulation layer, “t” is a thickness of the first film, T is a thickness of the insulation layer, λ is a wavelength of the acoustic wave, and t