Patent ID: 7973457

Claim:
A double rotation Y-cut crystal unit comprising: a crystal element, which is respectively rotated by an angle θ° and an angle φ° in a counterclockwise direction centering on an X axis and a Z axis of crystal axes (X, Y, Z), which principal surface is perpendicular to a Y″ axis of newly-generated rotated crystal axes (X′, Y″, Z′), and which is formed into a rectangular geometry longer in one direction, wherein when the X′ axis is rotated by an angle α° in the counterclockwise direction with the Y″ axis serving as a central axis in a plane of X′-Z′ of the rotated crystal axes serving as the principal surface, a direction of a long side of the crystal element corresponds to the rotated X′ axis direction, and wherein the angle α° is set to (30−φ)°±45°.