LiTaO3 crystal fork vibratory gyroscope

A new vibratory gyroscope using a LiTaO₃ crystal is proposed for a miniature angular rate sensor. A fork with a 130° rotated Y-cut plate has high electromechanical coupling factors and low temperature coefficients in both modes, the f_x mode and the f _y mode which are orthogonal to each other. Our trial fork has cuboid arms that are 7.0 mm long 1.0 mm wide, and 1.0 mm thick with a 0.3 mm gap. The fork has a high-Q resonance at 16 KHz in the two modes. The driving mode gives effective and stable self-oscillation as a resonator. The detecting mode slightly couples to the holder and its Q is about 500. This Q value is convenient for frequency adjustment during fabrication and as a sensor, for a quick rotation response. As a loading mass on the holder changes only the resonance frequency in the detecting mode, we can adjust the two resonance frequencies to within 1 Hz of each other. Our experimental results showed that a LiTaO₃ fork gyroscope can potentially be used as a miniaturized and sensitive angular rate sensor