Patent ID: 8256289

Claim:
An angular rate sensor, of which operations are in a three-dimensional coordinate system consisting of x, y, and z-orthogonal directions, based on a first and a second elastic acoustic wave propagating generated in an elastic material along the x and y-directions, respectively, in an elastic material on which a Coriolis force acts in response to a rotary motion of the angular rate sensor about the x-direction, comprising: a supporting member having a surface extending on an x-y plane created by an x and a y-direction which define the x and y directions, respectively, in the coordinate system; a plurality of perturbation masses located at anti-nodes of the first elastic acoustic wave and accommodated into the trench of the supporting member so as to vibrate in the z-direction coherently with the first elastic acoustic wave and to be displaced by the Coriolis force for generating a second elastic acoustic wave; a film disposed on the supporting member so as to enclose a predetermined area below which the plurality of the perturbation masses are formed, the film having an upper and a lower surfaces and being comprised of piezoelectric material, and having a surface portion at least including the surface of the supporting member for serving as the elastic material; a driving transducer disposed on the film comprised of piezoelectric material, for generating a first elastic acoustic wave having a predetermined wavelength, the driving transducer being in alignment with the predetermined area on which the plurality of the perturbation masses is formed; and a detecting transducer disposed on the upper surface of the film comprised of piezoelectric material, for detecting the second elastic acoustic wave so as to be adjacent to the predetermined area below which the plurality of the perturbation masses is formed and to be orthogonal to the driving transducer, for detecting the second elastic acoustic wave, and for providing an output indicative of the second elastic acoustic wave generated by the Coriolis force as a function of an angular rate of the rotary motion of the angular rate sensor itself.