Patent ID: 7994878

Claim:
An acoustic wave device comprising: a first medium of lithium niobate piezoelectric single crystal as the main constituent, and having a flat surface cut out in a theta θ rotated Y cut; a third medium containing aluminum oxide or nitrogen material as the main constituent; a second medium containing silicon oxide as the main constituent, and enclosed by the first medium and the third medium; and a reflector and IDT (inter-digital transducer) formed on the flat surface of the first medium, and enclosed by the first medium and the second medium; and the IDT mainly excites the boundary acoustic waves, wherein the IDT is included of metal containing aluminum as the main constituent; the reflector is a shorted type reflector; and when the wavelength of the boundary acoustic wave is set as lambda (λ), the thickness of the reflector as hr, the thickness of the second medium as h 1 , and the thickness of the IDT as hm, then: ( h 1+ hm )/λ≦77.0% 2.5≦ hr/λ≦ 8.5%.