Patent ID: 6940208
Filing Date: 2005-09-06
Classification: H03H

Abstract:
1. A surface acoustic wave device comprising: an elastic substrate; a dielectric thin film provided on the elastic substrate, at least one of said elastic substrate and said dielectric thin film being made of a piezoelectric material; and at least one of an IDT electrode and a reflector electrode disposed between the elastic substrate and the dielectric thin film, said at least one of said IDT electrode and said reflector electrode including at least one region where a strip is disposed within an interval defined by approximately a half-wavelength of the surface acoustic wave in the direction of propagation of the surface acoustic wave, and said strip being used for reflection of surface acoustic waves; wherein the duty ratio of the strip is greater than about 0.6; the thickness of said at least one of said IDT electrode and said reflector electrode is greater than about 0.01λ, wherein λ represents the wavelength of the surface acoustic wave ;and the dielectric thin film covers the strip of said at least one of said IDT electrode and said reflector electrode, the upper surface of the dielectric thin film covering the strip has a slope and protrudes with respect to a portion of the dielectric thin film where the strip is not disposed, and an inclination angle of the slope with respect to the upper surface of the dielectric thin film covering the strip is greater than about 30°.