A Four Million Quality Factor Cylindrical Resonator with Miniatured Design and Improved Metal Coating

A Cylindrical resonator gyroscope is a type of vibratory gyroscope with a core element of a symmetrical cylindrical shell resonator. Compared with hemispherical resonators, cylindrical resonators are easier to manufacture and can maintain relatively high quality factors. To control the vibration of the resonator and obtain accurate vibration signals, it is necessary to metallize the surface of the insulated surface of the fused silica resonator. The metal coating process should maintain the characteristics of the resonator with high quality factor and low frequency split. During the coating process, the presence of the residual stress in the film can cause an increase in the internal friction, and the quality factor of the resonator coated with Cr/Au bilayer film and Ti/Pt bilayer film is significantly lower than that before, which limits the overall performance of the resonator gyroscope. This paper reports a miniatured fused silica cylindrical shell resonator manufactured by precision grinding, the diameter of which is 12 mm, reduced by more than 50% than previously reported. The influence of film thickness and residual stress of the metal coating film on the quality factor of the resonator is studied by experiment. Films of Cr monolayer with different thicknesses are coated on cylindrical resonators by magnetron sputtering. The results show that quality factor of over 10 million is achieved before metal coating, and the quality factor of the cylindrical resonator with improved metal coating reaches more than four million.