Patent ID: 7589451

Claim:
A surface acoustic wave device comprising a piezoelectric substrate and an IDT that is formed on said piezoelectric substrate and is made from Al or alloy including Al as a main component, an excited wave being an SH wave, wherein said piezoelectric substrate is a rotation Y cut substrate made from a quartz flat substrate, where a cut angle θ of said piezoelectric substrate is a rotation angle of a crystal Z-axis when piezoelectric substrate is rotated around a crystal X-axis, a direction in which the piezoelectric substrate is rotated from a positive Z-axis side to a positive Y-axis side is a direction in which said cut angle θ is minus, and the cut angle θ is set in a range of −64.0°<θ<−49.3°, and a propagation direction of a SAW is set to (90°±5°) to a crystal X-axis, and when a wavelength of the SAW to be excited is represented as λ, an electrode film thickness H/λ standardized by a wavelength of said IDT is set to satisfy 0.04<H/λ<0.12.