LiTaO3 single-crystal tuning fork vibratory gyroscope

We proposed and tested a LiTaO3 single-crystal vibratory gyroscope with two orthogonal bending modes, the inner side vibration being the driving mode and the vibration orthogonal to that side being the detection mode. The gyr oscope has a 130 degrees rotating Y plate resonator, possesses a large elec tromechanical coupling coefficient and a high Q factor of 20,000 for the dr iving mode, and operates effectively near its resonant frequency. The detec tion mode is integrated with the substrate via the base, thus making it pos sible to adjust the resonant frequency and the Q factor. We also studied me thods to reduce leakage output through the detection electrodes used to mon itor driving signals, methods important to improving the characteristics of piezoelectric gyroscopes. Undesirable modes from the driving and detection electrodes were controlled by changing electrode geometry, while undesirab le electromechanical coupling was reduced by trimming the electrodes. We el iminated the mechanical coupling between the two orthogonal modes by laser trimming the corners of the tuning folk arms. By making the above adjustmen ts, we reduced overall leakage output and obtained a gyroscope of simple co nstruction with superior characteristics. (C) 1999 Scripta Technica, Electr on Comm Jpn Pt 2, 82(6): 82-90, 1999.