The null signal suppression of new type LiTaO3 piezoelectric gyroscope

To improve the sensitivity and stability of the piezoelectric gyroscope, the null signal suppression of leakage coupling between driving and detecting modes is the most important subject. A new H-type LiTaO₃ (LT) piezoelectric gyroscope for suppression of its inner leakage coupling consists of the driving fork, the detecting fork and the long rectangular median coupler. The new arrangement of the electrodes on arms can vibrate only the driving fork in the f_e mode but can detect the f_e mode in detecting fork due to the high electromechanical coupling coefficient of LT crystal. The resonance frequencies of the f_x and f_e modes are 14.9 kHz and 15.3 kHz. The Q values of the f_x and f_e modes are 20,000 and 6,000, respectively. The null signals due to the electrostatic leakage, the electromechanical leakage and the mechanical leakage, were suppressed totally less than -90 dB. This value is -40 dB compared with the conventional fork type. In spite of the nf=400 Hz, the sensitivity went up to O.11 mV/(/sec) driven 1 V_rms at 14.9 kHz