PURPOSE: To obtain a small-sized velocity meter, which can be mass-produced at low cost, by forming a vibrator in the shape of a beam supported on both ends by a base body.
CONSTITUTION: A lower electrode 4 is divided into an electrode 9 for driving and electrodes 8a, 8b for detection. When an upper electrode 6 is used as a common ground and an electric field having frequency close to the cantilever natural frequency of a vibrator 1 is applied to the electrode 9, cantilever vibrations are excited in the direction of V by the vibrations of a PZT piezoelectric film 5. When the vibrator 1 is moved in the direction V at velocity V, Coriolis force Fc works on the vibrator 1 when rotational angular velocity Ω is applied around the axis of a cantilever in the axial direction of the cantilever. The force deflects the vibrator 1 in the direction perpendicular to the direction of vibrations. When force is applied in the directions of Ω and Fc, compressive stress works on the electrode 8a side and tensile stress to the electrode 8b side. When voltage between the electrode 8a and a ground is represented by Va and voltage between the electrode 8b and the ground by Vb, a signal resulting from cantilever vibrations is offset in a signal by Coriolis force when difference Va-V2b of both voltage is taken, and only the signal by Coriolis force can be read.
WATANABE SHUNJI (JP)
SANGO YOSHITAKA (JP)
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